National Security Adviser John Bolton handed in his resignation Tuesday morning at President Donald Trump’s request, the president announced on Twitter

“I informed John Bolton last night that his services are no longer needed at the White House,” Trump tweeted. “I disagreed strongly with many of his suggestions, as did others in the Administration, and therefore I asked John for his resignation, which was given to me this morning. I thank John very much for his service. I will be naming a new National Security Advisor next week.”

Bolton has clashed with members of the Trump Administration. Recently, Bolton and Vice President Mike Pence reportedly objected to Trump inviting Taliban leaders to Camp David the week of the 9/11 anniversary.