A commercial cargo ship transiting the Strait of Hormuz was struck by a drone on 25 June, in what US President Donald Trump the following day called a “foolish violation” of the 18 June ceasefire memorandum between Washington and Tehran. Trump stated on his Truth Social platform that Iran had launched at least four one-way attack drones at vessels in the strait; one hit the upper deck of a “large and very expensive” ship, causing damage but no casualties, while US forces shot down the other three. The United Kingdom Maritime Trade Operations had earlier reported a vessel hit by an “unknown projectile” 14 kilometres off the Omani coast, with no environmental harm. The incident prompted the UN International Maritime Organization to suspend its evacuation of some 600 ships and 11,000 seafarers stranded in the Gulf since the outbreak of hostilities on 28 February.

Viewed from Washington, the attack is a direct test of the interim understanding that lifted mutual naval blockades and opened a 60-day window for negotiations on a permanent settlement. The White House, through a senior official, indicated it was assessing whether the strike constituted a formal breach, while Secretary of State Marco Rubio, concluding a Gulf tour, warned that any Iranian threat to shipping would mean “we have a problem.” A joint statement by the US and the Gulf Cooperation Council rejected Iran’s claim of authority over the strait and insisted on “free, unconditional and unrestricted navigation,” explicitly ruling out any transit fees.

Tehran, however, has advanced a sharply different interpretation of the memorandum. The Islamic Revolutionary Guard Corps declared that “the only authorised transit routes through the Strait of Hormuz are those designated by the Islamic Republic of Iran,” and warned that vessels using alternative corridors would not receive safety guarantees or insurance coverage. Deputy Foreign Minister Kazem Gharibabadi dismissed “ambiguous arrangements” and “parallel routes” not coordinated with Iran, while state media reported that three foreign tankers attempting an “unauthorised” passage were turned back. Iranian officials maintain that, under the memorandum, they are obliged only to facilitate safe passage for 60 days without tolls, but retain the sovereign right to regulate traffic and impose charges thereafter.

Regional capitals have responded with a mix of alarm and diplomatic engagement. The United Arab Emirates foreign minister held his first publicly announced call with his Iranian counterpart since the war began, stressing the need for full commitment to the interim deal. In Israel, Defence Minister Israel Katz warned that any Iranian attack would be a “grave mistake,” while a framework agreement between Israel and Lebanon was reportedly reached in Washington, adding a further layer to the regional diplomacy. Oil prices fell on Friday on initial optimism about the strait’s reopening, but shipping data showed traffic levels dropping back after a brief surge, and analysts in London cautioned that the crisis is far from resolved. The next round of technical talks between US and Iranian negotiators is expected before 30 June, with the communication line established under the memorandum now facing its most serious stress test.