Defense Secretary Pete Hegseth has told former Joint Chiefs of Staff Chairman Mark Milley that he is revoking his security detail and clearance and ordering a review of the retired general’s conduct to see whether his rank should be re-evaluated, the Pentagon said.

Hegseth, whose first day at the Pentagon was Monday, directed the Defense Department’s inspector general to look into “the facts and circumstances” surrounding Milley’s conduct “so that the Secretary may determine whether it is appropriate to reopen his military grade review determination,” Pentagon spokesman John Ullyot said.

The statement did not provide specific reasons for the moves, although Defense Department chief of staff Joe Kasper said, “Undermining the chain of command is corrosive to our national security, and restoring accountability is a priority for the Defense Department under President Trump’s leadership.”

Milley did not immediately respond to NBC News’ request for comment.

Milley had served as chairman of the Joint Chiefs of Staff under both former President Joe Biden and President Donald Trump during his first term, and he was at odds with Trump over various issues.

In 2020, Milley apologized for accompanying Trump to a photo-op in front of a church by the White House after the president ordered the violent removal of protesters demonstrating over the death of George Floyd.