LONDON (AP) — Britain accused Iran on Thursday of holding the world's economy hostage as diplomats from more than 40 countries held talks on ways to press Tehran to reopen the Strait of Hormuz, a vital oil route that has been choked off by the U.S.-Israeli war against Iran.

The U.S. didn't attend the virtual meeting, which came after U.S. President Donald Trump made clear that he thinks securing the waterway is not America’s job. Trump has also disparaged America's European allies for failing to support the war and renewed his threats to pull the U.S. out of NATO.

U.K. Foreign Secretary Yvette Cooper said the talks, which focused on political and diplomatic rather than military means, showed “the strength of our international determination" to reopen the strait. The 41 countries represented came from all continents except Antarctica, a reflection of the global tremors from a war that has sparked shortages of fuel and fertilizer and higher prices for food far beyond the Middle East.

“We have seen Iran hijack an international shipping route to hold the global economy hostage,” Cooper said at the start of the meeting. Cooper said “unsustainable” spikes in oil and food prices were “hitting households and businesses in every corner of the world.”

Shipping in the strait has slowed to a trickle

Iranian attacks on commercial ships, and the threat of more, have halted nearly all traffic in the waterway that connects the Persian Gulf to the rest of the globe’s oceans, shutting a critical path for the world’s flow of oil and sending petroleum prices soaring.

There have been 23 direct attacks on commercial vessels in the Gulf since the war began on Feb. 28, and 11 crew members have been killed, according to shipping data firm Lloyd’s List Intelligence.

Traffic through the strait has slowed to a trickle, with what remains dominated by sanctions-evading tankers carrying Iranian oil, Lloyd’s List Intelligence said in a briefing Thursday. It said a murky operation under which Iran vets who can pass continues to operate as Tehran maintains its chokehold over the key waterway.

In a televised address on Wednesday night, Trump said countries that depend on oil flowing through the Strait of Hormuz “must grab it and cherish it” — because the U.S. would not.

No country appears willing to try and open the strait by force while fighting rages and Iran can target vessels with anti-ship missiles, drones, attack craft and mines.

French President Emmanuel Macron said opening the strait by force is “unrealistic.”

The reopening of the strait “can only be done in coordination with Iran,” through negotiations that would follow a potential ceasefire, Macron told reporters Thursday during a visit to South Korea.

France is pushing for an international mission involving European and non-European nations to escort oil and gas tankers through the waterway after the most intense phase of the conflict is over. The British government said military planners from an unspecified number of countries will meet next week to plot ways to ensure security once the fighting ends, including potential mine-clearing work and “reassurance” for commercial shipping.

The U.K. hopes Thursday's meeting will help isolate Tehran and weaken its desire to block shipping. Cooper said participants — senior officials from countries including France, Germany, Italy, Canada, Japan and the United Arab Emirates — discussed increasing diplomatic pressure over Iran's “reckless” attacks and tightening economic screws to prevent Tehran profiting from control of the strait.

The meeting also discussed working with the U.N.'s International Maritime Organization to free 2,000 ships and 20,000 seafarers trapped by the conflict, she said.

No concrete measures were announced, however.

The meeting sends a message to Trump

The international effort idea has echoes of the international “coalition of the willing” that has been assembled, led by the U.K. and France, to underpin Ukraine’s security after a future ceasefire in that war. That coalition is, in part, an attempt to demonstrate to the Trump administration that Europe is stepping up to do more for its own security.

The urgency of stronger continental defenses has been reinforced by Trump’s renewed suggestion that the U.S. could leave NATO. He said Wednesday that the military alliance had “treated us very badly.”

David B. Roberts, reader in Middle East Security Studies at King's College London, said international coalition-building efforts over Hormuz are “definitely linked to the wider Trumpian antagonism toward NATO, that other members of NATO are not pulling their weight.

“Without a doubt, this is Britain and France, notably, trying to lead the way, to very visibly show a certain sort of utility” to the Trump administration.

“There’s also the very pragmatic reality that America is an oil exporter,” he added. “The immediate pressures about the fallout of the of the energy blockage in the Gulf, they fall on Europe and of course Asia, far more than America.”