President Donald Trump issued an ultimatum Wednesday for Iran to accept a deal to end the war or face renewed, more intense US bombing, in the latest of a series of abrupt policy shifts.
"Assuming Iran agrees to give what has been agreed to, which is perhaps a big assumption, the already legendary Epic Fury will be at an end," Trump posted on his Truth Social platform," using the US name for its campaign against Iran.
"If they don't agree, the bombing starts, and it will be, sadly, at a much higher level and intensity than it was before," he added.
Trump's post came after US news outlet Axios reported that Washington and Tehran were close to agreeing on a one-page memorandum of understanding to end the war and set a framework for more detailed nuclear negotiations.
Trump late Tuesday announced a pause in a US military operation to guide stranded commercial ships through the Strait of Hormuz -- after only a day -- citing a chance to seal a deal to end the war.
The US leader said Washington's blockade of Iranian ports would remain in place as Tehran kept up its own closure of the vital trade route, which has rocked markets and spiked fuel prices.
Trump wrote on social media that the decision to halt his so-called "Project Freedom" a day after it began came after requests from "mediator Pakistan and other countries", saying "Great Progress has been made toward a Complete and Final Agreement" with Tehran.
"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 finalized and signed," Trump wrote late Tuesday.