Trump decided to pull American forces back from Syria's northern frontier.

Syrian Kurds facing a Turkish military operation did not "help us in Normandy," US President Donald Trump said Wednesday, defending his widely-criticized decision to clear the way for the assault.

The Kurdish forces -- which the US partnered to combat the Islamic State group in Syria -- are "fighting for their land," Trump said.

"As somebody wrote in a very, very powerful article today, they didn't help us in the Second World War, they didn't help us with Normandy as an example," he said.

The president was apparently referring to a piece by a columnist on the conservative Townhall website supporting Trump's decision to pull American forces back from Syria's northern frontier, which opened the way for the Turkish operation.

Trump has faced a bipartisan storm of criticism since the White House made the surprise announcement on Sunday.

The Kurds "are there to help us with their land, and that's a different thing," said Trump.

"We have spent tremendous amounts of money on helping the Kurds in terms of ammunition, in terms of weapons, in terms of money, in terms of pay. With all of that being said, we like the Kurds," he added.

Brett McGurk, who served as the US envoy to the international coalition against the Islamic State group, has in the past disputed Trump's assertions on that subject, saying that the "weapons provided were meager" and "nearly all stabilization funding came from the @coalition.