The US has rescued the missing crew member of the US F-15 fighter jet which was shot down on Friday over southern Iran.

US 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.

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.

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.

The BBC understands there was an engagement between the US and Iranian forces during the rescue, and the pilot may have been injured during his initial ejection from the aircraft.

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 air force units behind CSAR missions include some of the most highly trained and specialised members of the military.

The missions are often conducted by helicopters, which fly low over enemy territory, alongside other military aircraft that conduct strikes and patrol the area.

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".

The president added the airman's location was monitored "24 hours a day" by senior US officials who were planning the rescue operation.

Trump said the US military sent dozens of aircraft into Iran and claimed the operation was carried out without any Americans being killed or wounded.

Iranian state media reported that troops from the Islamic Revolutionary Guard Corps (IRGC) shot down a US drone while it was searching for the missing airman.

The American drone crashed in Iran's southern Isfahan province, the IRGC's public relations office is quoted as saying, according to the semi-official Fars news agency.

Earlier, Iran had said it wanted to find the missing American alive and had 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 - assuming that they're physically capable, and not so injured that they can't move - 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.

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.

Two crew members were on board the jet which was shot down. The pilot of the jet 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 Islamic Revolutionary Guard Corps (IRGC) has said that nomadic tribes living in the country's mountains shot two Black Hawk helicopters that were part of the US rescue mission.

BBC Verify has confirmed a video from Friday showing what appears to be three armed individuals firing towards at least two Black Hawk helicopters.

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.

The Kohgiluyeh and Boyer-Ahmad region is a mountainous south-western province, home to more than 700,000 people, including nomads.

The nomads in the area are known to carry rifles to protect their herds and camps from wild animals and theft in the remote highlands.

The province of Khuzestan is a powerhouse for oil and several other industries. It is home to more than 4.7 million people, with a diverse population, including Arabs, Persians, Lors and other ethnic groups.

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.

This two-crew system allows the workload to be divided up, particularly in a congested environment where the pilot is trying to evade threats.

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).

Additional reporting by Ghoncheh Habibiazad, BBC Persian

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