Defense Secretary Pete Hegseth has fired the Navy chief of staff in a sudden shakeup following the confirmation of Hung Cao as the new Navy Under Secretary.

“Jon Harrison will no longer serve as the Chief of Staff of the Secretary of the Navy. We are grateful for his service to the Department,” a Pentagon spokesman told Military Times in a statement on Saturday.

At the time of publication, Harrison had not provided a comment about his ousting.

Harrison was a political appointee of President Donald Trump who had worked with Navy Secretary John Phelan on efforts to streamline the Navy’s policy and budgeting offices after coming into their posts with many of the Navy’s biggest programs years behind schedule.

Politico was first to report on the ouster.

An official, speaking on condition of anonymity because they were not authorized to speak to the press, said Harrison had attempted to limit the role of the undersecretary, Navy veteran Cao, and had reassigned aides meant to help Cao in his new role.

Cao, a Republican and strong Trump supporter, ran and lost in Virginia to Democratic opponents in races for both the House and Senate.

Hegseth has fired several top aides this year, including senior advisor Dan Caldwell, deputy chief of staff Darin Selnick and Colin Carroll, the chief of staff to the deputy secretary of defense.

He has also removed the chairman of the Joint Chiefs of Staff Gen. CQ Brown, Chief of Naval Operations Adm. Lisa Franchetti, Commandant of the Coast Guard Adm. Linda Fagan and several other uniformed leaders.

Harrison assumed the chief of staff role in January after having served in the first Trump administration as chairman of the United States Arctic Research Commission, a position he held until spring 2021.

In his address to Congress in March, Trump pledged to revive America’s struggling shipbuilding industry, announcing a new shipbuilding office in the White House to help the cause. That effort has since moved to the Office of Management and Budget following the ouster of shipbuilding advocate Mike Waltz from the National Security Council in the wake of the Signalgate scandal.

Waltz created a group chat on the encrypted messaging app Signal in March to discuss an impending U.S. military strike against Houthi rebels in Yemen. The Atlantic’s editor-in-chief, Jeffrey Goldberg, was mistakenly added and Hegseth shared sensitive information about the attack in the chat that originated from a classified email.

The Pentagon Inspector General’s office is still investigating the Signal incident.