After numerous disagreements on U.S. foreign policy, President Donald Trump said he has fired National Security Adviser John Bolton.

Bolton was hawkish in his approach when dealing with U.S. adversaries, and White House Press Secretary Stephanie Grisham said he and Trump disagreed on “many, many issues,” according to Bloomberg.

But the way the actual removal happened was a bit messy. Trump said in a tweet he asked for Bolton’s resignation Monday night because he “disagreed strongly with many of his suggestions.”

Bolton refuted those claims, though, in his own tweet, saying he “offered to resign last night” but the president wanted to talk about it Tuesday. Bolton was scheduled to attend a terrorism briefing before the news broke.

Trump and Bolton had butted heads on a number of issues regarding U.S. foreign relations. But what may have been the final straw was a disagreement over meeting with the Taliban at Camp David to try to negotiate an end to the war in Afghanistan — just before 9/11 on Wednesday, creating potentially bad optics.

The security adviser also didn’t agree with Trump’s attempts to cozy up to North Korean leader Kim Jong Un, and was mysteriously missing from the June announcement of the two leaders’ meeting, according to Bloomberg.

Earlier this summer, Hesamodin Ashna, adviser to Iranian President Hassan Rouhani, warned Trump of being misled into a conflict with Iran by Bolton, a noted war hawk.

Charlie Kupperman will fill Bolton’s role until a new adviser is announced, according to Deputy White House Press Secretary Hogan Gidley. But Kupperman has counseled Bolton for the last 30 years so his views likely align with the ousted adviser.