WASHINGTON: The internal watchdog looking into accusations against Secretary of State Mike Pompeo abruptly quit Wednesday, just months after his predecessor was fired.

The State Department's acting inspector general, Stephen Akard, is a longtime aide to Vice President Mike Pence and his installation in May had widely been seen as a way to keep a friendly figure in the role.

Akard informed colleagues he is "returning to the private sector after years of public service," a State Department spokesperson said.

"We appreciate his dedication to the department and to our country."

Robert Menendez, the top Democrat on the Senate Foreign Relations Committee, voiced alarm at the "leadership crisis" at the State Department and vowed that Congress would work to ensure an independent probe after Akard's departure.

Akard's departure comes just as his office finalizes a report on Pompeo's controversial decision to bypass Congress to sell $8.1 billion in arms to Saudi Arabia and other Arab allies.