President Donald Trump announced that acting White House chief of staff Mick Mulvaney would be replaced by Republican Rep. Mark Meadows of North Carolina.
"I am pleased to announce that Congressman Mark Meadows will become White House Chief of Staff. I have long known and worked with Mark, and the relationship is a very good one," Trump tweeted.
Trump, who did not immediately offer an explanation for the swap, thanked Mulvaney, who he said would become special envoy for Northern Ireland.
"I want to thank Acting Chief Mick Mulvaney for having served the Administration so well. He will become the United States Special Envoy for Northern Ireland," Trump added. "Thank you!"
Mulvaney has been a fixture of Trump's administration in various roles over the past three years.