President Donald Trump has accused Iran of shooting down a US helicopter over the Strait of Hormuz and vowed to respond to the attack out of "necessity".
Two crew members of the Apache helicopter that crashed following the attack were rescued by an American sea drone, the Pentagon said in a statement.
"There were two pilots involved, both are safe and uninjured," Trump wrote on Truth Social. "Nevertheless, the United States must, of necessity, respond to this attack."
It was not immediately clear what the US response would be, but any military action risks inflaming the shaky ceasefire with Iran once again. There has been no immediate response from Tehran on the US president's comments.
Iranian media appeared to acknowledge the incident, with the semi-official Mehr News Agency reporting that Iran had not claimed responsibility.
The prospect of US military action against Iran has emerged as Israeli forces carried out strikes across southern Lebanon on Tuesday.
Tehran had warned that Israeli attacks on southern Lebanon would trigger another wave of retaliatory strikes.
On Tuesday, minutes before Trump's comments on the downed American Apache helicopter, Iran's top negotiator in peace talks with Washington, Mohammad Baqer Qalibaf, took to social media to signal retaliation.
"We prefer the language of diplomacy, but we speak other languages far more fluently. Break your commitments, and we'll switch to what we speak best."
"You ride the horse you saddled!," he wrote.
Israel and Iran halted attacks on each other after exchanging fire over the weekend for the first time since April's truce.
Trump publicly told both countries to "immediately stop 'shooting'" because they were jeopardising negotiations between Washington and Tehran on a deal to end the regional war.
He said on Truth Social that Israel and Iran are looking to do "an immediate ceasefire" but peace is "subject to ignorance or stupidity getting in its way".
On Tuesday he also told journalists: "We're in the final throes of what will be a very, very good deal," adding that it could take "two or three days" and the Strait of Hormuz would open immediately after.
But now that the US believes the Iranians were responsible for the downing of its helicopter, domestic concerns will demand some kind of reaction.
Earlier, in its statement on Tuesday, US Central Command said the two crew members from the downed Apache had been rescued at 19:33 EDT (23:33 GMT) on Monday.
"Rescue efforts were led by US Naval Forces Central Command and the 82nd Airborne Division, with support from US Air Force and Navy units including US 5th Fleet's Task Force 59," the statement added.
A spokesman for Centcom told the BBC that the crew members were rescued by an unmanned surface drone that was operated by Task Force 59, a Bahrain-based unit launched ion 2024.
The unit looks after "the operational deployment of unmanned systems teamed with manned operators to bolster maritime security across the Middle East region".
The drone rescued the soldiers and transported them to another location on the water where they were then hoisted up to a helicopter for further transport, a centcom spokesperson said.
