US President Donald Trump departed on a secret military flight from Turkey last month when the White House said he was flying aboard Air Force One, an extraordinary move prompted by an Iranian assassination threat, the Washington Post reported.

Trump had taken the newly renovated Qatari-donated jet to Ankara for the NATO summit but he unexpectedly used an older Air Force One when departing, a move that prompted questions about the newer plane’s security.

The trip to NATO was the first international travel for the new plane, whose speedy upgrades triggered questions over its cost and security, and took place as hostilities escalated with Iran, which borders Turkey.

Before departing Ankara, Trump said on Truth Social that he would use an older baby blue Air Force One plane “for old time’s sake” to RAF Mildenhall in Britain while the new plane stopped at the same base so US service members stationed there could tour the aircraft.

After Trump boarded the old Air Force One in front of cameras in Ankara, he was secretly shuttled by an airport catering truck to a smaller plane, an Air Force C-32A, the Post reported citing a US official familiar with the operation and corroborating material it reviewed.

The deception operation was triggered by a credible threat to Trump, the Post reported.

A similar operation had taken place in 2000, when President Bill Clinton used an unmarked executive jet to fly into Pakistan while sending his formal Air Force One as decoy.

On this occasion, the journalists who thought they were travelling with Trump on the older Air Force One, which was effectively used as a decoy, reported being advised to keep their window shades in the press cabin closed.

The Post said aside from reporters, some White House staff also believed that the president was on board.

When asked later by reporters why they had to keep their shades shut during the flight, Trump said it was because they were “probably on a dangerous flight.” He went onto say: “But if I go, you go. Right?”

The C-32A carrying Trump flew to Britain and arrived while the older Air Force One and media, landed minutes later, the Post reported. It was not clear, the paper said, how Trump was moved from the C-32A back to the older Air Force One.

Reuters video on July 8 captured Trump climbing the steps of an older Air Force One in Ankara with his travelling press pool reporting that he deplaned at 10.56pm local time.

He gave press a peace sign but didn’t walk over to talk to them. He then spent some time greeting service members before walking to the new, Qatar-donated plane, according to pool reports from that day.

When asked for comment on the revelation of a secret flight on a third plane, the White House provided a statement from Communications Director Steve Cheung saying the Qatari-donated jet has been fitted with high-level security protocols that ensure the safety of the president and his staff.

“As the president has said recently, there are many enemies of America who have their sights on him, and we use every tool at our disposal to address those threats,” Cheung said.

The Pentagon did not immediately respond to a request for comment.