French President Emmanuel Macron and the United Kingdom's Prime Minister Keir Starmer will cohost a video-conference with international leaders on Friday, aiming to chart a plan to secure the Strait of Hormuz.

The office of the French president said it would lead talks on a "multilateral and purely defensive mission" to restore freedom of navigation in the strait when security conditions allow.

The statement said "nonbelligerent" countries willing to contribute to the mission would take part, though names of other participating countries were not specified.

A spokesperson for the UK prime minister's office said: "The summit will advance work toward a coordinated, independent, multinational plan to safeguard international shipping once the conflict ends."

In a social media post, Starmer said Britain had convened "more than 40 nations who share our aim to restore freedom of navigation".

"The ongoing closure of the Strait of Hormuz is deeply damaging. Getting global shipping moving is vital to easing cost-of-living pressures," Starmer said.

Earlier in the week, Macron said on X that the initiative would aim to establish a "peaceful multinational mission" to secure maritime routes through the strategic waterway, stressing it will be "strictly defensive" and separate from the parties to the conflict. He said the mission would be deployed "as soon as circumstances permit".

French Foreign Minister Jean-Noel Barrot told Radio France Internationale on Tuesday that "several dozen countries" had already taken part in "preparatory work led in particular by the chiefs of staff to define the framework for such a mission". "It is a matter of coordinating with the coastal states," he added.

The announcement came after US President Donald Trump said a blockade on Iranian ports would take effect on Monday.

US-Israeli strikes on Iran have set off a region-wide war that has choked traffic through the strait, a vital artery for global oil and gas.

The US announcement of a naval blockade came after weekend talks between Washington and Tehran in Pakistan, aiming to end the war that began on Feb 28, collapsed.

The United Nations maritime agency's chief said on Monday that no nation has the legal right to close the Strait of Hormuz.

"In accordance with international law, no country has the right to prohibit the right of innocent passage or the freedom of navigation through international straits that are used for international transit," Secretary-General Arsenio Dominguez, head of the International Maritime Organization, told a news conference.

"De-escalation is what is going to start helping us address the crisis and bring shipping back to the way that we used to operate," he added.