Trump announced the move in a tweet a day after his new communications director, Anthony Scaramucci, accused Priebus of leaking information to reporters in a profanity-laced tirade.

Kelly, 67, who retired from the Marine Corps, was most recently secretary for the Department of Homeland Security.

Trump issued his decision just as he landed aboard Air Force One after a visit to Long Island. Priebus was on the plane with the Republican president.

“I will continue to serve as a strong supporter of the president’s agenda and policies,” Priebus said in a statement a short while later. “I can’t think of a better person than General John Kelly to succeed me.”

Trump had lost confidence in Priebus, privately questioning his competence after major legislative items failed to pass the U.S. Congress, a Trump confidant said.

A source close to Priebus said the former Republican National Committee chairman turned in his resignation on Thursday night, after Scaramucci’s rant against him was published by the New Yorker magazine.

A senior White House official said Trump had informed Priebus two weeks ago that he would be replacing him and that the move had no connection to Scaramucci, whose hiring a week ago prompted Sean Spicer, a Priebus ally, to abruptly resign as press secretary.

After frequent conversations with Kelly, Trump recently warmed up to the idea of naming Kelly chief of staff to more effectively manage personnel and offered it to him earlier this week, a senior White House official said.

Kelly starts on Monday.

Carrying an umbrella, Trump approached reporters as he stepped off Air Force One, with rain storming down.

“Reince is a good man. John Kelly will do a fantastic job. General Kelly has been a star, done an incredible job thus far, respected by everybody. He’s a great, great American. Reince is a good man,” Trump said.

Priebus’ 189-day tenure was the shortest in modern history for a White House chief of staff. He had hoped to stay on at least a year but struggled to manage his unpredictable boss and was unable to get a handle on conflicting factions in the White House who have frequently squabbled.

Trump loyalists had chafed at Priebus, feeling he had installed his RNC allies at the White House and overlooked the people close to Trump who helped get him elected president in November.

But Priebus allies felt he was an important link to establishment Republicans in Washington as the capital attempted to adjust to the anti-establishment style of the president.

“He has served the president and the American people capably and passionately,” House of Representatives Speaker Paul Ryan said of his friend in a statement. “He has achieved so much, and he has done it all with class. I could not be more proud to call Reince a dear friend.”