US Army Secretary Dan Driscoll has resigned after about 18 months in the post, becoming the latest senior military figure to leave President Donald Trump's administration.
Driscoll's departure was confirmed by CBS, the BBC's US media partner, which reported that the resignation came after months of tension and clashes between him and US Defence Secretary Pete Hegseth. However, the details of the conflict between the two officials have not yet been made public.
The White House praised Driscoll's work, calling him a "highly effective" leader in advancing Trump's agenda to strengthen the U.S. military. In a statement to CBS, the administration also said Driscoll had provided "exceptional leadership" during military operations.
Driscoll, 41, is the youngest secretary in the history of the US Army and during his time in office became known by the nickname associated with President Trump, "drone man", due to his strong support for new technologies used on the battlefield.
His resignation comes at a time of significant changes in the Pentagon's leadership. Driscoll is one of several senior military leaders to leave office recently. Among them is Navy Secretary John Phelan, who resigned unexpectedly in April. Also leaving their posts were Army Chief of Staff Randy George, Army Gen. David Hodne and Maj. Gen. William Green.
Since taking over the Pentagon, Pete Hegseth has fired more than a dozen senior US military officers. Among them have been the head of Navy operations and the vice chief of staff of the Air Force.
According to CBS, one factor that may have contributed to the clash between Driscoll and Hegseth is the Army secretary's close relationship with Randy George. Driscoll and George are reported to have been good friends, while George was reportedly one of the officials Hegseth had asked to resign.
The Secretary of the Army is the highest-ranking civilian official in charge of the U.S. Army. He oversees the active-duty forces of the Army, as well as the National Guard and Reserves. Dan Driscoll had previously served in the U.S. Army. He became an officer in 2007, later leading a cavalry platoon and was deployed to Iraq for several months in 2009.
While leading the Army, Driscoll was noted for his interest in advanced military technologies, particularly drones and other new combat systems. This approach also earned him the nickname Trump's "drone man."
