United States Army Secretary Dan Driscoll has resigned from his post, submitting his letter to President Donald Trump, according to three sources with knowledge of the situation who spoke to CNN.

The departure was described by one source as expected, given the sustained friction between Driscoll and Defence Secretary Pete Hegseth over recent months.

White House spokesperson Anna Kelly acknowledged the resignation in a statement, saying: “Secretary Driscoll has been highly effective in advancing President Trump’s agenda to Make America Strong Again at the Department of the Army by providing outstanding leadership during historic military operations, restoring an emphasis on readiness and lethality, assisting with negotiations between Russia and Ukraine, and more.”

Driscoll, an Army veteran and close personal friend of Vice President JD Vance, has served during a turbulent period at the Pentagon.

His resignation comes six months into the Iran war, which continues without a clear resolution in sight.

The split between Driscoll and Hegseth is not the first sign of instability at the top of the Army’s leadership. Earlier this year, Hegseth removed Army chief of staff General Randy George along with two other generals.

Driscoll and George had worked closely together during their time in their respective roles, and the firing of George is widely seen as part of the broader pattern of tension that ultimately contributed to Driscoll’s exit.