The prospect of a US service member alive and on the run in Iran raised the stakes for Washington as the conflict entered its sixth week with scant prospect of peace talks in sight and polls showing low public support.
With Iran's leadership defiant since the start of the war, its foreign minister left the door open in principle for peace talks with the US via mediation from Pakistan, but gave no sign of Tehran's willingness to bow to Trump's demands.
"We are deeply grateful to Pakistan for its efforts and have never refused to go to Islamabad. What we care about are the terms of a conclusive and lasting END to the illegal war that is imposed on us," Foreign Minister Abbas Araqchi said on X.
Trump has sent mixed messages since the conflict began with a US-Israeli bombardment of Iran on February 28, switching between hinting at diplomatic progress and making threats to bomb the Islamic Republic "back to the Stone Ages".
On Saturday, he repeated his threats to intensify attacks on Iran if it failed to reach a deal or open the key Strait of Hormuz waterway.
"Remember when I gave Iran ten days to MAKE A DEAL or OPEN UP THE HORMUZ STRAIT. Time is running out - 48 hours before all Hell will reign (sic) down on them. Glory be to GOD!" he said in a post on Truth Social.
In an apparent move to heap further pressure on Tehran following Trump's ultimatum, a senior Israeli defence official said Israel was preparing to attack Iranian energy facilities, and was awaiting the green light from the US
The time frame for such attacks would be within the next week, the official said.
Trump has previously threatened to hit Iranian power plants if his demands were not met.
The war has killed thousands, sparked an energy crisis and threatened lasting damage to the world economy.
Iran has virtually shut the Strait of Hormuz, which normally carries about a fifth of the world's oil and liquefied natural gas.
Iran attacked an Israel-affiliated vessel with a drone in the strait, setting the ship on fire, Iran's state media said on Saturday, citing the commander of the Revolutionary Guards' navy.
The downing of two US warplanes shows the risks still facing US and Israeli aircraft, despite assertions by Trump and his Defence Secretary Pete Hegseth that US forces had total control of the skies over Iran.
Iranian fire brought down a two-seat US F-15E jet, officials in both countries said on Friday, and a US official said search-and-rescue efforts had recovered one of the crew.
Two Black Hawk helicopters engaged in the search for the missing crew member were hit by Iranian fire but made it out of Iranian airspace, the two US officials told Reuters.
Iran's Islamic Revolutionary Guard Corps said it was combing a southwestern area near where the pilot's plane came down, while the regional governor promised a commendation for anyone who captured or killed "forces of the hostile enemy".
In a separate incident, an A-10 Warthog fighter aircraft was hit and crashed over Kuwait, with the pilot ejecting, the US officials said. Iranians, pummelled by air power since the US and Israel began their attacks, celebrated their success.
The Khatam al-Anbiya joint military command said it used a new air-defence system on Friday, which targeted a US fighter jet, three drones and two cruise missiles.
"The enemy should know that we rely on new air-defence systems built by the young, knowledgeable, and proud people of this country, unveiling them one after another in the field," a Khatam al-Anbiya spokesperson said, according to Iran's state media.
"The enemy should know that we rely on new air-defence systems built by the young, knowledgeable, and proud people of this country, unveiling them one after another in the field," a Khatam al-Anbiya spokesperson said, according to Iran's state media.
The Revolutionary Guards said they had targeted various areas in Israel in a wave of missiles and drones.
