US President Donald Trump has announced on Tuesday that 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.
"We have mutually agreed that, while the Blockade will remain in full force and effect, Project Freedom ... will be paused for a short period of time to see whether or not the Agreement can be finalised and signed," Trump wrote on social media.
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 by threatening to deploy mines, drones, missiles, and fast-attack craft. The United States has countered by blockading Iranian ports and mounting escorted transits for commercial vessels.
The US military said on Monday it had destroyed several Iranian small boats, as well as cruise missiles and drones.
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