Risk-averse NATO allies refuse to join US blockade of Iranian ports, opting to wait until the fighting stops

The initiative aims to establish rules for safe passage and the coordination of military vessels to escort tankers, Starmer said in parliament on Monday.

"Let me be very clear, this is about safeguarding shipping and supporting freedom of navigation once the conflict ends. Our shared aim here is a coordinated, independent, multi-national plan," he said.

A meeting to draw up plans for the mission involving about 30 countries, including Persian Gulf countries, India, Greece, Spain, Italy, the Netherlands and Sweden, could happen as soon as Thursday in Paris or London, a French diplomatic source said.