World leaders gathered in Paris on Friday called for the permanent reopening of the Strait of Hormuz and announced ongoing military planning for an international maritime security mission, even as Iran and the United States declared the strategic waterway open to commercial vessels under a 10-day ceasefire arrangement.

French President Emmanuel Macron and British Prime Minister Keir Starmer, who have jointly led diplomatic and military planning efforts, welcomed the ceasefire announcement but stressed it must become lasting and unconditional. Speaking after a conference attended by representatives of some 50 nations — including more than 30 heads of state and government, with German Chancellor Friedrich Merz and Italian Premier Giorgia Meloni present in person and leaders from Australia, Canada, South Korea and Ukraine joining by video — Macron said: "We all demand the full, immediate and unconditional reopening of the Strait of Hormuz by all parties." Starmer said a planned international mission would be deployed "as soon as conditions allow," with military planners set to meet in London next week.

The Strait of Hormuz, a narrow waterway between Iran and the Arabian Peninsula through which roughly a fifth of the world's oil normally passes, has been effectively closed since fighting began on February 28. The closure sent petroleum prices soaring and left dozens of nations scrambling to cushion the economic fallout from a conflict they did not join. The Paris conference, formally titled the Strait of Hormuz Maritime Freedom of Navigation Initiative, is explicitly limited to non-belligerent countries; the United States is not part of its planning.

German Chancellor Merz said Berlin could contribute mine-clearance and maritime intelligence capabilities to the mission, but would require parliamentary approval and a secure legal basis — ideally a United Nations Security Council resolution. He also expressed a desire for U.S. participation, saying it "would be desirable." Analysts caution, however, that the practical scope of any coalition operation is likely to be modest. Sidharth Kaushal of the Royal United Services Institute think tank said mine-clearing and maritime warning systems were more feasible roles than escorting tankers, which would require "huge numbers of vessels that nobody has." Iran expert Ellie Geranmayeh of the European Council on Foreign Relations added that European-led mine-clearing would be preferable to a U.S.-led operation, since a continued American military presence near Iranian shores risked renewed military miscalculation.

The mission is taking shape against a backdrop of transatlantic friction: U.S. President Donald Trump has criticised allies for not joining the war effort, while insisting the U.S. Navy's blockade of Iranian ships and ports will remain in force until a deal with Iran is finalised. For many European states, the initiative represents an opportunity to demonstrate an independent capacity for global security — even as questions remain about how many countries can actually commit meaningful military resources to the effort.