WASHINGTON (AP) — Under fire for his handling of the coronavirus crisis, President Donald Trump on Friday announced a major staff overhaul, naming Rep. Mark Meadows as his new chief of staff and replacing Mick Mulvaney, who has been acting in the role for more than a year.

Trump announced the surprise staff reshuffle in a series of Friday night tweets, saying Mulvaney would become the U.S. special envoy for Northern Ireland.

“I have long known and worked with Mark, and the relationship is a very good one,” he wrote, thanking Mulvaney — who never shook his “acting” title — “for having served the Administration so well.”

The long-rumored move makes Meadows, who announced he was not seeking reelection for his House seat from North Carolina, effectively Trump’s fourth chief of staff since taking office in 2017.

The decision comes as the Trump administration has faced criticism for its handling of the novel coronavirus outbreak. Mulvaney had been leading the interagency response to the virus until Trump designated Vice President Mike Pence to lead the whole-of-government effort more than a week ago.

Mulvaney has been marginalized inside the White House for months, taking on a more and more narrow role. And Trump has been eyeing the change for months, but wanted to wait until after impeachment, according to a person familiar with his thinking who spoke on condition of anonymity because the person was not authorized to discuss it publicly.

Mulvaney’s allies, however, had long brushed off rumblings off his imminent departure and had said as recently as last month that he planned to stay at least through the election in November.