A letter from President Donald Trump to Turkish President Recep Tayyip Erdogan was worded in such an unbelievable manner that people, including senior White House correspondents, thought it was fake.

In the Oct. 9 letter, which was released by the White House on Wednesday, Trump warns Turkey’s leader against invading northern Syria.

“Dear Mr. President: 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,” the letter begins.

Trump urges Erdogan to negotiate with Kurdish forces, then concludes by saying, “Don’t be a tough guy. Don’t be a fool! I will call you later.”

The letter was written the same day that the Turkish military launched an offensive against Kurdish forces in northern Syria after Trump’s Oct. 6 order for U.S. troops to withdraw from the region ― a decision that was met with bipartisan condemnation and that leaves the lives of U.S.-allied Kurds in jeopardy and risks the re-emergence of ISIS.

When Trump’s letter was first reported by Fox Business, many Twitter users presumed it to be satire or a hoax, and White House journalists felt the need to clarify when tweeting it that it was, in fact, real: