Navy Secretary John Phelan has been fired, a US official and a person familiar with the matter said on Wednesday, in another wartime shakeup at the Pentagon coming just weeks after Defence Secretary Pete Hegseth ousted the Army’s top general.

The Pentagon announced his departure in a brief statement, saying he was leaving the administration “effective immediately.” But it did not provide a reason or say whether it was his decision to go.

The sources, who spoke on condition of anonymity, said Phelan was dismissed in part because he was moving too slow to implement reforms to speed shipbuilding and because he had fallen out with key Pentagon leadership.

One source cited bad relationships with Hegseth, Hegseth’s deputy, Steve Feinberg, as well as the Navy’s No 2 civilian, Hung Cao, who the Pentagon said will now take over as acting Navy secretary. The source also cited an ethics investigation into Phelan’s office.

A billionaire seen as having close ties to President Donald Trump, Phelan is the first administration-picked service secretary to be fired since Trump came back into office last year.