US Army Chief of Staff Randy George was fired on Thursday by Defense Secretary Pete Hegseth, two US defense officials and a source familiar with the matter told Reuters, in the latest purge among the Pentagon's most senior ranks.

Hegseth, a former Fox News host, has moved quickly to reshape the department, firing generals and admirals as he seeks to implement US President Donald Trump's national security agenda.

The Pentagon confirmed that George, who had more than a year left in his term, "will be retiring from his position as the 41st Chief of Staff of the Army effective immediately."

The Pentagon said in a statement it was grateful for George's decades of service. "We wish him well in his retirement," it said.

The department did not give a reason for his departure, which comes as the US military builds up its forces in the Middle East while carrying out operations against Iran.

The strikes in the region are largely being carried out by the Navy and Air Force, although US Army soldiers have been dispatched to the Middle East for air defense systems. The Army is the largest branch of the US military, with about 450,000 active-duty soldiers.

Thousands of soldiers from the US Army's elite 82nd Airborne Division have also started arriving in the Middle East, potentially for ground operations in Iran.

There had been no public signs of friction between Hegseth and George, even as Hegseth pursued controversial moves such as firing the Army's top lawyer and arranging a massive military parade celebrating the Army’s 250th birthday, which coincided with Trump's birthday.

Earlier this week, however, Hegseth reversed an Army decision to investigate Army pilots who were flying attack helicopters near ‌singer Kid Rock's house, in an apparent show of support for the vocal Trump backer.

CBS News, which first reported George's dismissal, said his firing was not related to the Kid Rock incident. An official said Hegseth's former military aide and Army vice chief of staff, General Christopher LaNeve, will take over George's role in an acting capacity.

George, an infantry officer who served in Iraq and Afghanistan, was confirmed to the top Army post in 2023. Terms in that role usually run for four years.

Prior to holding the top job, George was the vice chief of the Army and, before that, the senior military adviser to then-Defense Secretary Lloyd Austin.

He was considered close to Army Secretary Dan Driscoll. The two worked together to take on large defense companies, in the Army's drive to speed up weapons development and drive down costs.

George's removal adds to recent upheaval at all levels of leadership at the Pentagon, including the firing last year of the previous chairman of the Joint Chiefs of Staff, Air Force General C.Q. Brown, as well as the chief of naval operations and Air Force vice chief of staff.

The office for George did not immediately respond to a request for comment.