US President Donald Trump has said his chief of staff John Kelly will leave his post at the end of the year.
Mr Kelly, a retired Marine general, has been in the role since the end of July last year.
Mr Trump did not name his successor, and is expected to announce the new chief in the next day or two.
Mr Trump made the announcement at the White House before departing for the Army-Navy American football game in Philadelphia.
He said: "John Kelly will leaving – I don't know if I can say retiring – but he's a great guy.
"We'll be announcing who will be taking John's place – it might be on an interim basis. I'll be announcing that over the next day or two, but John will be leaving at the end of the year.
"He's been with me almost two years now, between two positions.
"I appreciate his service very much."
Mr Kelly is credited with bringing some discipline to the White House, but his time with Mr Trump has not bee smooth sailing.
The shake up comes as Mr Trump prepares for what could be a challenging time from January when the Democrats take over the House after the mid-term elections. He also faces his next campaign for the 2020 presidential elections.
It's also despite Mr Trump asking his chief to stay on until 2020 when he reached the end of his first year. CNN also reported that the president had asked Mr Kelly to consider committing to his second term.
CNN also suggests that Mr Trump and Mr Kelly are no longer on speaking terms. Aides are said to believe the relationship between the pair cannot bounce back now, despite Mr Kelly allegedly being close to quitting on several occasions.
Mr Kelly moved from the Department of Homeland Security to chief of staff after Reince Priebus left. He took over as intrigue grew because of allegations of election interference from Russia.
Mr Trump has made several changes to his top team in the past few days, announcing his nomination for UN ambassador as former Fox News presenter Heather Nauert.
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Two of his staff who worked on his 2016 campaign will leave their roles to begin working on the re-election campaign. Bill Stepien has been Mr Trump's political director, and Justin Clark was the director of the office of public liaison.