US President Donald Trump has used Twitter to announce he has named Homeland Security Secretary John Kelly as White House chief of staff.
Mr Kelly replaces Reince Priebus, who has been in a feud with Mr Trump's new communications director, Anthony Scaramucci.
"I am pleased to inform you that I have just named General/Secretary John F Kelly as White House Chief of Staff. He is a Great American and a Great Leader. John has also done a spectacular job at Homeland Security. He has been a true star of my Administration," Trump said on Twitter.
He thanked Mr Priebus "for his service and dedication to his country".
"We accomplished a lot together and I am proud of him!"
White House staff were reportedly not told about Mr Priebus' sacking, finding out via Twitter, according to Time. Mr Priebus was reportedly told two weeks ago.
Mr Priebus didn't want Mr Trump to hire Mr Scaramucci, who yesterday said Mr Priebus' ouster was imminent.
"Reince is a f**king paranoid schizophrenic, a paranoiac," Mr Scaramucci told The New Yorker in an unhinged, profanity-filled interview.
The shake-up comes just hours after the Republican effort to overturn Obamacare failed, after three Republicans crossed the floor to vote against it.
Mr Kelly, 67, a retired four-star Marine Corps general, was most recently secretary for the Department of Homeland Security. He was hired with the goal of bringing more discipline to the White House, a senior White House official said.
Mr Trump issued his decision just as he landed aboard Air Force One after a visit to Long Island and hours after Republican efforts to repeal Obamacare failed in the Senate.
Mr Priebus was on the plane. He later told CNN he backed Mr Trump's decision.
"The President has a right to hit a reset button. I think it's time to hit the reset button. He intuitively determined that it was time to do something different, and I think he's right."
His tenure was the shortest of any White House chief of staff in history.
Reuters / Newshub.