イラン・米国によるホルムズ海峡封鎖：タンカー、緊張、そして代理戦の構図

On July 1, Iranian state media released a video in which officials of the Islamic Revolutionary Guard Corps (IRGC) asserted that the Sultanate of Oman is cooperating with Tehran on a fee‑collection scheme for vessels transiting the Strait of Hormuz. The broadcast, aired by ARY News, quoted an IRGC spokesperson saying that Oman “recognizes the legitimacy of Iran’s right to levy a passage fee” and will “facilitate the collection of the charge from ships that use the waterway.” No official response from Omani authorities has been recorded, and the claim has not been corroborated by independent observers or the International Maritime Organization.

The fee proposal follows a series of IRGC directives issued in late June that require all commercial traffic to follow a navigation route designated by the Guard. On June 26, the IRGC ordered four oil tankers to turn back from the strait after a projectile struck the Panama‑flagged tanker Kikuh, and on June 28 the Guard reiterated that any vessel deviating from its prescribed lanes would be treated as a hostile target. The July 1 statement appears to extend Tehran’s leverage from purely security‑based restrictions to an economic instrument, potentially reshaping the calculus for regional shipping firms that have already been rerouting cargoes around the Gulf or accepting heightened war‑risk premiums.

U.S. officials have not publicly addressed the fee claim. The Pentagon’s last statement, issued on June 28, framed the airstrikes on Iranian radar installations near Bandar Abbas and a missile‑storage complex in Khuzestan as a “proportionate and necessary” response to recent IRGC attacks on commercial vessels. Since those strikes, no additional missile, drone, or small‑arms engagements have been verified by satellite imagery, commercial AIS data, or on‑the‑ground reports from Oman, the United Arab Emirates, or India. The most recent incident involving a commercial ship remains the June 27 projectile attack on the Kikuh, which damaged its steering gear but did not result in casualties.

Regional actors continue to issue cautious statements. India, which has repeatedly protested U.S. strikes that killed three Indian seafarers in June, has called for the safety of its nationals but has not commented on the fee proposal. Oman’s maritime authority, which earlier in June announced a joint committee with Iran to oversee navigation in the strait, has so far refrained from confirming any financial arrangement. The United Arab Emirates, which signed a nuclear memorandum of understanding with Iran on June 21, has not linked that agreement to the current maritime dispute.

Commercial shipping companies remain split on how to respond. Some operators have opted to continue using the IRGC‑designated lane, citing the lack of an alternative corridor that meets their schedule and cargo‑type requirements, while others have shifted to the longer route around the Cape of Good Hope or to the Red Sea‑Suez corridor, citing the uncertainty surrounding both the security environment and the emerging fee structure. Insurers have kept war‑risk premiums near their June peak, reflecting the continued possibility of sudden escalations.

Analysts note that the fee claim could serve multiple Iranian objectives: it reinforces Tehran’s narrative of sovereign control over the strait, generates a potential revenue stream to offset sanctions‑related losses, and places pressure on Oman to choose between economic cooperation with Iran and its longstanding security partnership with the United States and Gulf Cooperation Council states. Whether Oman will formalize any fee‑collection mechanism remains unclear, and the lack of an official Omani statement leaves the proposal in a speculative stage.

Absent any new confirmed attacks, boardings, or seizures, the operational status of the Strait of Hormuz remains unchanged from the June 28 assessment: the United States maintains an exclusion zone that permits vessels with explicit permits to transit, while Iran continues to enforce its closure order through the IRGC’s maritime authority. The situation persists as a stalemate, with diplomatic rhetoric intensifying but no further kinetic actions reported in the Gulf of Oman or the strait itself.

No new incidents involving U.S. or Iranian forces have been reported in the Gulf of Oman or the Strait of Hormuz since the series of U.S. precision airstrikes disclosed on June 28. The Pentagon’s statement that the strikes targeted radar installations near Bandar Abbas and a missile‑storage complex in Khuzestan remains the latest confirmed action. Iranian state media have repeated the IRGC’s warning that all vessels must follow the navigation route set by the Revolutionary Guard, but no additional drone, missile, or projectile attacks on commercial shipping have been verified by independent observers or regional authorities.

A development would be any of the following: a confirmed strike—by missile, drone, or small arms—on a commercial or military vessel; the boarding, seizure, or disabling of a tanker by either side; a new declaration from Tehran or Washington that alters the status of the strait, such as a partial reopening, an extension of the exclusion zone, or a diplomatic overture; the release of satellite imagery or video that shows combat actions not yet reported; or statements from regional governments—Oman, the United Arab Emirates, India, or others—indicating casualties, rescues, or changes to navigation advisories.

In the absence of such evidence, commercial shipping firms continue to rely on alternative routes or await guidance from the Persian Gulf Strait Authority. Insurers maintain elevated war‑risk premiums, and the risk environment remains high, with both sides citing the other’s rhetoric as justification for maintaining their respective maritime postures. Until new, verifiable actions emerge, the stalemate persists.

U.S. forces escalated their campaign in the Gulf on June 28, launching a series of precision airstrikes against Iranian air‑defense installations and missile‑launch sites after an IRGC‑operated drone struck the Panama‑flagged tanker Kikuh in the Strait of Hormuz on June 27. The strikes, reported by multiple news outlets, targeted radar arrays near Bandar Abbas and a missile‑storage complex in the province of Khuzestan, marking the first direct U.S. attack on Iranian territory since the June 20 re‑closure of the strait. Pentagon officials said the operations were “proportionate and necessary” to deter further attacks on commercial shipping, while Iranian state media condemned the action as an “unjustified act of aggression” that violated international law.

Iran’s Islamic Revolutionary Guard Corps responded on June 27 by issuing a warning that all vessels transiting the Hormuz corridor must follow the IRGC‑designated navigation route, a directive broadcast in a Moneycontrol video on June 28. The IRGC’s maritime authority reiterated that any ship deviating from the prescribed lanes without explicit Iranian approval would be treated as a hostile target. The warning follows the IRGC’s June 26 order for four oil tankers to turn back from the strait, a move the corps described as enforcing Iran’s sovereign right to control maritime traffic after a recent projectile strike near Oman damaged the Kikuh’s steering gear.

The projectile attack on the Kikuh, described by Iranian officials as retaliation for U.S. airstrikes, was captured in a Fox News segment on June 27. The vessel, en route from Saudi Arabia to the United Arab Emirates, sustained steering damage but remained afloat; its crew reported no injuries. The incident prompted the International Maritime Organization to pause scheduled evacuations of non‑essential personnel from the Gulf, citing heightened risk to civilian shipping.

Regional diplomatic activity continued amid the heightened military posture. On June 23, Iran and Oman announced the formation of a joint committee to oversee navigation and dispute resolution in the Hormuz corridor, a development highlighted in a Geo News broadcast on the same day. The committee, comprising senior naval officers from both countries, pledged to “maintain safe passage for commercial vessels” while respecting Iran’s security concerns. Oman’s foreign ministry, however, reiterated its call for all parties to refrain from actions that could further destabilize the waterway, emphasizing the need for a multilateral de‑escalation framework.

India’s Ministry of External Affairs issued a statement on June 28 expressing “deep concern” over the latest U.S. strikes and the ongoing threats to Indian‑flagged and India‑linked vessels in the region. The ministry urged both Washington and Tehran to exercise restraint and called for an immediate resumption of diplomatic talks aimed at reopening the strait for legitimate trade. New Delhi also reminded the United Nations that the safety of its 24 seafarers rescued after the June 10 missile strike on the Palau‑flagged MT Maravex remains a priority.

U.S. Central Command, in a briefing held on June 28, affirmed that the exclusion zone around the Strait of Hormuz remains in effect and that any vessel attempting to breach the zone without a valid permit will be intercepted. The command added that the recent airstrikes are part of a broader “containment strategy” designed to neutralize Iran’s capability to launch anti‑ship missiles from coastal sites. No U.S. casualties were reported in the latest operations.

Analysts note that the convergence of Iranian maritime orders, U.S. kinetic actions, and the newly established Iran‑Oman committee creates a complex risk environment for commercial shipping. Insurers have raised premiums for vessels transiting the Hormuz corridor, and several major oil companies have announced temporary rerouting of tankers through the Cape of Good Hope. The situation remains fluid, with the possibility of further escalatory steps hinging on whether Tehran escalates drone or missile attacks and whether Washington expands its strike campaign beyond the identified targets.

Iran’s Islamic Revolutionary Guard Corps (IRGC) reiterated its closure of the Strait of Hormuz on June 20, citing the continued presence of U.S. warships and Israeli activity in Lebanon as justification for halting all commercial traffic. The announcement, made through the IRGC’s maritime authority, echoed earlier closure orders issued on June 11 and June 19, but added that the “temporary suspension will remain in effect until the United States withdraws its forces from the region.” No U.S. official has confirmed a change in the operational status of the exclusion zone, and the United States has not issued a new statement on the strait’s accessibility since its June 13 clarification that the waterway remains open for vessels with proper permits.

On June 21, Tehran issued a separate declaration linking the closure to a recently signed nuclear memorandum of understanding (MOU) between Iran and the United Arab Emirates. The IRGC warned that any ship attempting to transit without explicit Iranian approval would be treated as a hostile target, framing the move as retaliation against what it described as “unilateral nuclear diplomacy that undermines regional security.” The United Arab Emirates has not publicly responded to the MOU‑related warning, and U.S. Central Command reiterated that its enforcement posture continues to focus on preventing illicit oil shipments rather than policing the strait’s legal status.

Amid the heightened tension, Iran and Oman announced a joint committee on June 23 to oversee navigation and safety in the Hormuz corridor. The committee, comprised of senior officials from Oman’s Ministry of Transport and the IRGC’s maritime command, is tasked with coordinating vessel scheduling, sharing real‑time intelligence on maritime threats, and establishing a fee structure for services rendered within the waterway. Both governments released statements affirming “sovereign rights” over the strait and pledging to “maintain free and secure passage for legitimate commercial traffic.” Oman’s Sultan also met with top Iranian officials in Muscat, where the two sides discussed the possibility of a limited, fee‑based transit regime that could allow certain vessels to pass under strict oversight. No concrete timetable for implementing the fee system has been disclosed, and the United Nations’ International Maritime Organization has not yet issued guidance on the proposed arrangement.

The IRGC’s maritime authority issued a further operational directive on June 26, ordering four oil tankers that had entered the strait to turn back to their ports of origin. The order was accompanied by a warning that any vessel attempting to transit without prior approval would be subject to “immediate defensive action,” including the use of drones. Video released by Iranian state media on the same day showed an IRGC‑controlled drone striking a cargo vessel near the Omani coast, causing minor damage but no reported casualties. The incident marks the first confirmed IRGC drone attack on a non‑Iranian commercial ship since the series of U.S. missile strikes on Palau‑flagged tankers in early June.

In parallel, Iran ordered all ships to obtain explicit clearance from its maritime authority before entering the Hormuz corridor, effectively extending its control beyond the previously declared closure. The directive, broadcast on Iranian television and posted on the IRGC’s official website, cited “recent hostile actions by foreign powers” as the rationale for tighter oversight. Shipping companies operating in the region have responded by rerouting vessels around the Arabian Sea, citing the increased risk of interdiction and the lack of clear, internationally recognized navigation guidelines.

No new U.S. military actions have been reported in the Gulf of Oman or the Strait of Hormuz since the June 13 Hellfire missile strike on the Palau‑flagged Lian Star. U.S. Central Command’s last public briefing, issued on June 14, reiterated that the United States remains committed to enforcing its maritime exclusion zone and monitoring Iranian activities, but offered no comment on the latest Iranian orders or the Iran‑Oman joint committee. Regional insurers continue to raise premiums for voyages that must pass through or near the strait, reflecting the persisting uncertainty over whether a diplomatic de‑escalation or further militarization will shape the next phase of the crisis.

No confirmed incidents involving U.S. or Iranian forces have been reported in the Gulf of Oman or the Strait of Hormuz since the Hell‑fire missile strike on the Palau‑flagged Lian Star on June 13. The most recent publicly available material is a June 14 video broadcast by NDTV that provides a live tracker of tanker movements but offers no new evidence of attacks, boardings, or missile launches. Official statements from U.S. Central Command and the IRGC Navy released on June 13 remain unchanged: the United States continues to enforce a maritime exclusion zone around the strait, while Iran maintains its closure order and warns that any vessel attempting to transit will be targeted.

A development would be any of the following: a verified missile, drone, or small‑arms strike on a commercial or military vessel; the boarding, seizure, or disabling of a tanker by either side; a new declaration from Tehran or Washington altering the status of the strait—such as a partial reopening, an extension of the blockade, or a diplomatic overture; the release of additional video or satellite imagery showing combat actions; or statements from regional governments (e.g., Oman, the United Arab Emirates, India) indicating casualties, rescues, or changes to navigation advisories.

In the absence of such reports, commercial shipping firms continue to rely on alternative routes or await guidance from the Persian Gulf Strait Authority. The risk environment remains elevated, and insurers and ship operators are still factoring the possibility of sudden escalation into their operational planning. Until fresh evidence emerges, the maritime standoff persists in a static, high‑tension posture.

No new incidents involving U.S. or Iranian forces have been reported in the Gulf of Oman or the Strait of Hormuz since the Hell‑fire missile strike on the Palau‑flagged Lian Star on June 13. The latest official statements from U.S. Central Command and the IRGC Navy, released on June 13, remain unchanged: the United States continues to enforce a maritime exclusion zone around the strait, while Iran maintains its closure order and warns that any vessel attempting to transit will be targeted.

A development would be any of the following: a confirmed missile, drone, or small‑arms attack on a commercial or military vessel; the boarding, seizure, or disabling of a tanker by either side; a new declaration from Tehran or Washington altering the status of the strait—such as a partial reopening, an extension of the blockade, or a diplomatic overture; the release of additional video or satellite evidence showing combat actions; or statements from regional governments (e.g., Oman, the United Arab Emirates, India) indicating casualties, rescues, or changes to their navigation advisories.

In the absence of fresh reports, the situation remains a stalemate. Both sides continue to cite the other’s actions as justification for maintaining their respective maritime postures, and commercial shipping companies are still navigating the heightened risk environment by seeking alternative routes or awaiting further guidance from the newly created Persian Gulf Strait Authority. Until new evidence emerges, the daily log will reflect the ongoing impasse without additional incidents.

June 13 2026 – US missile strikes on commercial tankers intensify; Iran closes the Strait of Hormuz

U.S. Central Command confirmed that on June 13 a Hell‑fire missile struck the Palau‑flagged tanker Lian Star in the Gulf of Oman, the latest precision strike aimed at vessels it says are attempting to breach a naval blockade of the Strait of Hormuz. The attack followed a series of similar engagements, including a June 10 missile strike on the Palau‑flagged MT Maravex that ignited a fire and required the rescue of all 24 Indian crew members, and a June 9 fighter‑jet‑launched munition that disabled an oil tanker bound for Iran after the crew ignored repeated commands.

The U.S. has justified the strikes as enforcement of sanctions and an effort to prevent Iranian oil from reaching international markets. Video released by the Navy on June 12 showed the Hell‑fire missile impact on an India‑linked tanker, and a separate clip posted by the Pentagon depicted the disabling of the Lian Star. In each case, U.S. officials said the vessels had either entered a designated exclusion zone or attempted to run the blockade.

Iran’s Islamic Revolutionary Guard Corps (IRGC) responded by announcing a full closure of the Strait of Hormuz on June 11, citing the “U.S. blockade” as an act of aggression. The IRGC Navy warned that any ship attempting to transit the waterway would be targeted, and it invoked the newly created Persian Gulf Strait Authority—established in May—to regulate traffic and impose fees. Iranian officials also threatened retaliation against U.S. bases in the region, echoing earlier statements by Mojtaba Khamenei that warned of a broader war front if the United States continued its maritime operations.

The escalation has drawn diplomatic protests. India summoned a senior U.S. diplomat on June 12 after three Indian sailors were killed in the June 10 strike on the Maravex and additional crew members were reported missing following the June 13 attack on the Lian Star. Indian officials called for an immediate halt to U.S. strikes on commercial vessels and urged Washington to respect the safety of its nationals. The United Kingdom and the United Arab Emirates have also issued statements urging restraint, while the United Nations has called for both parties to avoid actions that could further jeopardize the free flow of oil through the strait.

In the meantime, commercial traffic remains severely disrupted. Iranian authorities reported that, despite the closure, a limited number of vessels—primarily those with explicit permits from the IRGC‑controlled authority—have been allowed to pass under strict supervision. However, satellite imagery and AIS data indicate a sharp decline in transits compared with the pre‑crisis average of 35 ships per day recorded in late May.

U.S. officials maintain that the blockade is legal under international law, pointing to United Nations Security Council resolutions that authorize interdiction of vessels carrying sanctioned Iranian oil. Critics argue that the repeated use of precision missiles against civilian‑flagged tankers risks violating the principle of proportionality and could be deemed an unlawful use of force.

The situation remains fluid, with both sides signaling a willingness to intensify military posturing. Analysts note that any miscalculation—particularly a direct engagement between U.S. warships and IRGC naval units—could trigger a broader regional conflict, underscoring the strategic importance of the Hormuz corridor for global energy markets.

US Navy Disables Iranian Tankers as Gulf Tensions Rise

June 2, 2026 — The United States Navy disabled three Iranian tankers in the Gulf of Oman on June 1, prompting the Islamic Revolutionary Guard Corps to threaten massive retaliation and warn of opening new war fronts, according to statements from IRGC officials and US defense officials.

The naval engagement marks the most significant direct combat between US and Iranian maritime forces since the Hormuz crisis escalated in late April. IRGC Navy spokesman Admiral Ali Raza Tangsiri issued a statement vowing to target American military installations across the region, the semiofficial Fars News Agency reported. The threat followed a video message from Supreme Leader Ayatollah Ali Khamenei's son, Mojtaba Khamenei, who warned of retaliation and predicted Israel's collapse following what he described as US aggression in the Gulf.

President Donald Trump confirmed the US strikes in a post on social media, writing that American forces "had no choice" after Iranian vessels attempted to breach what the administration has described as a lawful naval interdiction operation. The White House has maintained that US operations in the strait are enforcement of sanctions targeting Iranian oil exports.

The June 1 strikes came as US-Iran ceasefire negotiations over the broader Iran-Israel conflict appeared to stall over the issue of Strait of Hormuz access. Iran has insisted any agreement include guarantees of unimpeded commercial transit through the waterway, which carries roughly one-fifth of the world's daily oil supply. Washington has refused to accept what it characterizes as preconditions.

Earlier in the week, Trump threatened action against Oman, which borders the Strait of Hormuz, accusing Muscat of failing to prevent Iranian military operations emanating from its territory. The threat, which raised concerns among regional trading partners, drew condemnation from Oman and further complicated diplomatic efforts.

The IRGC separately reported June 1 that 25 to 26 ships had transited the strait in the preceding 24 hours, including oil tankers engaged in energy trade. The figure marks a slight increase from previous days but remains far below normal traffic levels, reflecting ongoing reluctance among major shipping insurers and operators to risk passage through contested waters.

Iran's Revolutionary Guard Corps has issued a new navigation advisory demanding all vessels coordinate with Iranian military headquarters before entering the Strait of Hormuz, warning that ships entering without authorization will face potential attacks, according to statements from the IRGC Navy reported May 4.

The directive, which included the release of a new map outlining zones under IRGC control, comes amid a fresh wave of competing claims between Tehran and Washington over incidents in the narrow waterway. The UAE separately accused Iran of striking an oil tanker in the strait on May 4, marking the first allegation of damage to a third-party commercial vessel since the escalation began.

President Donald Trump announced May 4 that the United States would resume what he called "Hormuz War" operations after what administration officials described as Iranian missile strikes targeting American warships in the strait. The IRGC separately released statements declaring itself the sole "guardian" of the waterway, a framing Iranian officials have used to reinforce claims of sovereign control over the passage that carries roughly one-fifth of the world's daily oil supply.

The competing narratives could not be independently verified. The White House provided no immediate evidence supporting the missile strike claims, while Iranian officials denied targeting US naval vessels. The exchange marks the most direct military posturing between the two sides since the strait's closure was announced April 18.

Global oil markets climbed further May 4, extending the four-year high reached May 3 following reports that Iran's oil production had declined under the combined effect of the US naval blockade and IRGC restrictions on tanker transits. Brent crude rose 2.3 percent in Asian trading before pulling back on uncertainty surrounding the actual extent of disruptions.

India, whose flagged vessels have been targeted twice since mid-April, summoned Iran's ambassador for the second time in two weeks to demand guarantees for the safety of its mariners. European Union foreign policy chief Kaja Kallas called for an emergency video conference of senior diplomats later May 4 to discuss de-escalation options, according to a statement from the bloc's diplomatic service.