LIVE | 'Whole civilisation will die tonight': Trump warns Iran

Those injured were the weapon systems officer from the US Air Force F-15E fighter jet that was shot down in Iran late last week as well as two aircrewmen from a helicopter that took fire during the initial rescue for the pilot from the downed jet.

That's according to a US official, who spoke to AP on Monday on condition of anonymity to discuss a sensitive military operation.

After rescuing the pilot, the HH-60 Jolly Green II helicopters were “engaged by every single person in Iran who had a small arms weapon, and one of the aircraft, the trailing aircraft, took several hits,” said Gen Dan Caine, chairman of the Joint Chiefs of Staff.

At a White House briefing, Trump said the jet's downed weapons officer was “bleeding profusely” but still able climb mountainous terrain and communicate his location.

The US and Egypt are pushing Israel not to strike the main Lebanon-Syria border crossing, according to Lebanon's General Security chief, Hassan Choucair.

He those “ongoing contacts” by Washington and Cairo aim to protect and reopen the Masnaa border crossing.

It's been closed since Saturday after Israel warned it could be targeted over alleged weapons smuggling by the Lebanese militant group Hezbollah. Officials in Lebanon and Syria deny that claim, saying vehicles are thoroughly inspected.

The crossing's closure has forced travellers to take a longer northern route. More than 200,000 people have crossed from Lebanon into Syria since the war escalated five weeks ago, many of them fleeing the conflict.

The United States relied on dozens of aircraft, hundreds of personnel, secret CIA technology and a dose of subterfuge to rescue a two-man F-15E fighter jet crew downed deep inside Iran.

Trump and his top defence aides detailed the daring rescue operation in an unusual level of detail during a news conference at the White House on Monday.

The US surged helicopters, midair refuellers and fighter jets deep into Iran to rescue the pilot within hours. But finding and picking up the jet's weapon systems officer was a more complicated endeavour.