President Donald Trump wrote Turkish President Recep Tayyip Erdogan an extraordinary letter warning him not to be "a tough guy" or "a fool" as his forces launched their attack on northern Syria, a White House official confirmed to NBC News.
"Dear Mr. President," the October 9th letter began, "Let's work out a good deal! You don't want to be responsible for slaughtering thousands of people, and I don't want to be responsible for destroying the Turkish economy — and I will."
Trump then referred to economic sanctions his administration used on the country to push for the release of an American pastor who'd been locked up in Turkey, calling it "a little sample" of what could be in store.
"I have worked hard to solve some of your problems. Don't let the world down. You can make a great deal," Trump wrote, asserting that the commander of the Kurdish forces is "willing to negotiate with you."
"History will look upon you favourably if you get this done the right and humane way," Trump wrote to Erdogan. "It will look upon you forever as the devil if good things don't happen. Don't be a tough guy. Don't be a fool!"
"I will call you later," the letter concludes. It's signed, "Sincerely, Donald Trump."
The letter was first reported by Fox Business Network, and the White House official confirmed its contents.
Appearing on CNN, David Gergen, who has been an adviser to several presidents, said the letter "had such an adolescent quality to it" that when he first saw it, he assumed it was fake.
"When I read it, I immediately called my research assistant and said, 'See if this is fake. I just can't believe the White House sent this out,'" Gergen said.
"It is unprecedented to the best of my knowledge, and I do think it makes it tougher to work with Turkey, which is a member of NATO, and we need to figure out a way to get this stopped short of much more violence."
According to the BBC, Erdogan put the letter "in the bin".