US President Donald Trump was whisked off a plane through a catering container to another aircraft in a covert operation to mask his location over a threat from Iran.

The Washington Post first reported the details of the clandestine operation which happened last month when Trump travelled to Ankara, Turkey, for a NATO summit.

A US official told The Post that the president boarded the old Air Force One jumbo jet in view of television cameras, and then was secretly shuttled minutes later to a smaller plane via an airport catering truck typically used to load meals and other supplies preflight.

Trump and other officials had said publicly that he would be leaving Turkey on July 8 aboard one of the older versions of Air Force One rather than a luxury 747-8 donated by Qatar that he had flown in on. White House officials had expressed concerns that the Qatari plane lacked certain security measures and noted that the aircraft will soon be further retrofitted.

Officials told CBS News that the US detected a credible Iranian threat to fire a missile at the plane Trump intended to board.

The threat posed by Iran, which was considered extremely serious and immediate, included the possible use of shoulder-to-air missiles. The threat came as the US renewed its attacks on Iran.

According to authorities, the move to use the other plane was a “snap decision”.