The US has rescued the missing crew member of the US F-15 fighter jet which was shot down on Friday over southern Iran.
President Donald Trump confirmed the rescue on social media on Sunday morning after the US military "pulled off one of the most daring Search and Rescue Operations" in its history. The officer is "now SAFE and SOUND!" he added, though in a later post Trump said he had been "seriously wounded".
Two crew members were on board the jet, and both ejected from the plane. One of them had already been rescued by US forces.
Iranian officials said the warplane was shot down by its air defence system.
Details around the rescue operation and how it unfolded are still emerging. Here is what we know so far.
How was the officer rescued?
The US and Iran were in a race to locate the missing crew member after the jet was downed over southern Iran.
The exact circumstances of the US rescue remain unclear, but one person familiar with the operation described it as a "huge" combat search and rescue mission in southern Iran.
Trump paused a number of other operations in Iran to focus on the rescue, directing dozens of special operations forces personnel to the effort, the BBC's US partner CBS reported.
"This type of raid is seldom attempted because of the danger to 'man and equipment.' It just doesn't happen!" the president said on social media.
The rescue of crew members of a downed jet is one of the most complex and time-sensitive operations - known as combat search and rescue (CSAR) - that the US military and its allies prepare for.
The missions are often conducted by helicopters, which fly low over enemy territory, alongside other military aircraft that conduct strikes and patrol the area.
William Fallon, a retired US Navy admiral, told the BBC that time of day probably worked in the mission's favour. "Darkness is better for our people because they're used to operating at night," he said.
In his social media post, Trump said the airman - a colonel - "was behind enemy lines in the treacherous mountains of Iran, being hunted down by our enemies, who were getting closer and closer by the hour".
Mikey Kay, military analyst and host of the Security Brief on BBC News, said ejection from an aircraft is "a brutal process" that "can produce massive forces on the body".
Kay said that as soon as he was on the ground he is likely to have gathered the parachute and concealed it. He would be trained to get the beacon signal on, get to high ground, conceal himself and establish communications.
Officials told US media that the crew member spent more than 24 hours on his own, hiding in the mountains and hiked up a 7,000ft (2,000m) ridge line.
The president added the airman's location was monitored "24 hours a day" by officials who were planning the rescue operation.
After he was rescued, he was flown to Kuwait to receive treatment for his injuries, CBS said quoting US officials.
Media reports said the CIA played a crucial role in the rescue by tracking the airman and passing his exact location to the Pentagon.
The agency engaged in a deception campaign inside Iran, reports said. While the rescue attempt was taking place, it spread word the airman had already been found and was being extracted.
Trump said the US military sent dozens of aircraft into Iran and claimed the operation was carried out without any casualties.
Two transport planes that were intended to fly out rescue crews were unable to take off from a remote base inside Iran, and were then destroyed to keep them out of enemy hands, US media said. Commandos then flew out after three extra aircraft were sent.
Earlier, Iran offered a reward to citizens for help in finding them.
The crew of a downed jet are highly trained for such situations.
"Their number-one priority is to stay alive and to avoid capture," Jennifer Kavanagh, director of military analysis at think tank Defense Priorities, told the BBC.
"They're trained to... try to get away from the ejection site as quickly as possible, and to conceal themselves so that they are safe."
They're also trained on survival techniques so that they can go without food or water, or find resources from the local terrain, for as long as possible, Kavanagh said.
Where and when was the jet shot down?
Iranian state media first claimed on Friday that the country's forces shot down a US jet over its southern region.
The exact location where the F-15 was reportedly downed was unconfirmed, but two possible provinces were mentioned in Iran's state media - Kohgiluyeh and Boyer-Ahmad, and Khuzestan.
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Two crew members were on board. The pilot was recovered in an earlier operation. That operation reportedly included an A-10 Warthog aircraft which was hit over the Gulf, with its pilot ejecting before being rescued.
One helicopter carrying the rescued pilot from the F-15E jet was hit by small arms fire, injuring crew members on board - but it landed safely, US media reported.
Iran's top joint military command has credited new Iranian air defence systems with the downing of both US warplanes, according to Iran's state-affiliated IRNA news agency.
What do we know about the jet's purpose?
The F-15E is designed for both air-to-ground and air-to-air missions. In Iran, they are most likely to have been involved in defensive roles to shoot down Iranian drones and cruise missiles.
In its air-to-ground strike role, the jet is capable of dropping laser and GPS guided precision munitions, as well as other bombs.
The aircraft has two crew: the pilot and a weapons systems officer in the back seat. The weapons officer, known as a "Wizzo", is responsible for selecting targets and making sure the weapons are programmed for the appropriate attack.
We do not know what specifically brought down this US jet, but if it was taken down by the Iranians, the most likely reason is a surface-to-air missile (SAM).
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