Navy Secretary John C. Phelan departed the Trump administration effective immediately on Wednesday, the Pentagon announced. Pentagon spokesman Sean Parnell confirmed Phelan's departure in a statement posted to social media.

Navy Undersecretary Hung Cao will serve as acting secretary of the Navy following Phelan's departure. In his statement, Parnell said the Secretary of Defense and Deputy Secretary of Defense expressed gratitude to Phelan for his service to the Department and the United States Navy.

Phelan had served in the role for just over a year, having taken the position approximately 13 months ago. The departure comes as the latest in a series of high-level defense leadership changes within the administration.

The timing of Phelan's departure was unexpected, occurring just one day after he addressed a large gathering of sailors and industry professionals at the Navy's annual conference in Washington, D.C. During that event, he also spoke with reporters about his ongoing agenda and priorities for the service.

The Pentagon has not provided specific details about the reasons for Phelan's departure or the circumstances surrounding the timing of his decision to leave the administration.