US President Donald Trump said on Tuesday he would briefly pause an operation to help escort ships through the Strait of Hormuz, citing “great progress” toward a comprehensive agreement with Iran.

Hours earlier, US Secretary of State Marco Rubio had outlined the effort that began on Monday to escort stranded tankers out of the Gulf. The strait has been virtually shut since the conflict began, blocking some 20 per cent of world oil supplies and igniting a global energy crisis.

“Based on the request of Pakistan and other Countries, the tremendous Military Success that we have had during the Campaign against the Country of Iran and, additionally, the fact that Great Progress has been made toward a Complete and Final Agreement with Representatives of Iran, we have mutually agreed that, while the Blockade will remain in full force and effect, Project Freedom (The Movement of Ships through the Strait of Hormuz) will be paused for a short period of time to see whether or not the Agreement can be finalized and signed,” Trump wrote on his Truth Social platform.

There was no immediate reaction from Tehran, where it was early on Wednesday morning.

Shortly after Trump’s post, US crude oil futures fell $2.30 and broke below $100 per barrel, a much-watched threshold since the conflict sent energy prices soaring two months ago.

The White House did not immediately reply to a request for comment on what progress had been made, or how long the pause would last.

Rubio and other senior administration officials said earlier on Tuesday that Iran could not be allowed to control traffic through the strait.

Iran has effectively sealed off the strait since the US-Israeli campaign began at the end of February. The US has countered by blockading Iranian ports and mounting escorted transits for commercial vessels.

The US military escorts over the last day and a half — dubbed “Project Freedom” by Trump — drew Iranian attacks, threatening an already fragile ceasefire.

Iran’s Revolutionary Guards navy warned of a “firm response” if ships deviated from its approved route through the strait, as the country’s chief negotiator said Tehran “had not even started yet,” following a spate of attacks in the crucial trade route.

Rubio says main operation is over

Rubio told reporters at the White House that the US had achieved its objectives in its military campaign, which was launched on February 28 alongside Israel.

“Operation Epic Fury is concluded,” Rubio said. “We’re not cheering for an additional situation to occur.”

“This is not an offensive operation; this is a defensive operation,” Rubio said. “And what that means is very simple — there’s no shooting unless we’re shot at first.”

Rubio said the United States has “achieved the objectives” of the war.

“These guys are facing, they are facing real, catastrophic destruction to their economy,” he said, while adding that Trump still preferred a negotiated deal with Iran.

One of Trump’s central objectives in launching military strikes against Iran was to ensure Tehran does not develop a nuclear weapon, something Tehran has denied seeking. However, Iran has not handed over more than 900 pounds of highly enriched uranium.

US Defence Secretary Pete Hegseth said earlier on Tuesday that the US had successfully secured a path through the waterway and that hundreds of commercial ships were lining up to pass through. The four-week-old truce with Iran was not over, he added.

“Right now the ceasefire certainly holds, but we’re going to be watching very, very closely,” he said.

General Dan Caine, chairman of the US Joint Chiefs of Staff, said Iranian attacks against US forces fell “below the threshold of restarting major combat operations at this point”.

Asked what Iran would need to do to violate the ceasefire, Trump said: “They know what not to do.”