The US Navy chief is leaving his position “effective immediately,” according to the Pentagon.

The Pentagon revealed on Wednesday that US Navy Secretary John Phelan is leaving the Trump administration. In a social media statement, Pentagon spokesman Sean Parnell stated that his retirement will be “effective immediately”. The position is primarily administrative, and Navy Undersecretary Hung Cao will fill it on an acting basis.

Phelan is the most recent senior military figure to depart the administration in recent months. His resignation coincides with the ongoing US blockade of the Strait of Hormuz and the US-Israel war with Iran.No explanation has been given by the Navy. According to unverified accounts in US media, his departure followed conflict within the US leadership over shipbuilding-related concerns.

“On behalf of the Secretary of War and Deputy Secretary of War, we are grateful to Secretary Phelan for his service to the Department and the United States Navy,” Parnell wrote. “We wish him well in his future endeavors.”

Only a few weeks have passed since US Defense Secretary Pete Hegseth requested that Army Chief of Staff Randy George resign. Recently, Gen. David Hodne and Maj. Gen. William Green, two more Army officials, were also dismissed.

Hegseth has dismissed over a dozen top military personnel since joining the Pentagon, including the vice chief of staff of the Air Force and the chief of naval operations. According to insiders who talked to several news sites, Phelan was fired after he and Hegseth clashed over the execution of Trump’s shipbuilding project.

The secretary’s duties are primarily administrative and include developing policies, hiring, training, and outfitting the Navy, as well as managing finances and logistics such as building and maintaining naval installations and ships. After being nominated by President Donald Trump in 2024, Phelan, a civilian with no prior military experience, was sworn in as Secretary of the Navy in March 2025. The businessman contributed significantly to Trump’s campaign.

When Trump declared in December that the US would commission a new class of heavily armed Navy “battleships” named after himself as part of a redesigned “Golden Fleet” that Phelan endorsed, the two made an appearance together at Mar-a-Lago.

Phelan’s successor, Cao, a 25-year veteran of the Navy, was appointed undersecretary in October 2025.

With Trump’s support, he unsuccessfully challenged Democratic incumbent Senator Tim Kaine for the US Senate in Virginia in 2024. He attacked the military’s diversity, equity, and inclusion programs during a campaign debate.

Trump’s announcement that the US blockade of Iranian ports would continue despite a ceasefire in the war coincided with the Navy’s command shift. Iran claimed to have “seized” two ships in the Strait of Hormuz, a crucial international shipping route that supplies a large portion of the world’s oil. Conflicts in this area have persisted.

White House Press Secretary Karoline Leavitt said the president is “satisfied” with the ongoing US naval blockade on Iranian ports, and “understands Iran is in a very weak position”.