Air Force One stopped at Ramstein Air Force Base in south-westGermany on his way back from Iraq, where he had visited US troops in harm’s way for the first time, two years into his presidency.

Mr Trump walked along a rope line at the US base in German state Rhineland-Palatinate, shaking hands, posing for selfies, and autographing “Make America Great Again” hats for servicemen.

He also met Air Force generals aboard his aircraft at the base.

His earlier visit to Al Asad base in Al Anbar, Iraq, was his first to USforces in harm’s way overseas. The base was once on the front line of the war against ISIS, facing suicide bombers and experiencing regular mortar attacks in 2015. Trump has claimed responsibility for defeating ISIS.

During a speech to troops at Al Asad base, he said that unlike in Syria, he had no plans to bring home the roughly 5,000 troops stationed in Iraq. The 2,000 US troops in Syria could return home because of military gains against ISIS, he said.

The president’s trip was unannounced and shrouded in secrecy. But aviation enthusiasts watching aircraft trackers spotted Air Force One travelling over Europe despite Mr Trump having no scheduled visits, sparking speculation of a Christmas visit to the troops in the Middle East.