US Secretary of the Navy John C. Phelan is departing the administration "effective immediately," Pentagon spokesman Sean Parnell said Wednesday.
"We are grateful to Secretary Phelan for his service to the Department and the United States Navy. We wish him well in his future endeavors," Parnell said in a statement
Undersecretary Hung Cao will become acting secretary of the Navy, he added.
Phelan was tapped for the post by President Donald Trump last year and was confirmed by the Senate in a 62-30 vote.
During his confirmation hearing before the Senate Armed Services Committee, he pledged to work to improve the US Navy by addressing recruitment and retention in the branch as well as increase the Navy's fleet among other issues.
Defense Secretary Pete Hegseth has dismissed a number of officials during Trump's second term.
In early April, the Pentagon announced that Gen. Randy A. George will retire from his role as the 41st Chief of Staff of the Army "effective immediately."
More than a dozen senior military officers have been fired by Hegseth, including Joint Chiefs of Staff Chairman Gen. C.Q. Brown Jr., Chief of Naval Operations Adm. Lisa Franchetti, Air Force Vice Chief of Staff Gen. James Slife and Defense Intelligence Agency head Lt. Gen. Jeffrey Kruse.