US Navy Secretary John Phelan is leaving the Trump administration, the Pentagon announced on Wednesday.
His departure will be "effective immediately", Pentagon spokesman Sean Parnell said in a social media post. Navy Undersecretary Hung Cao will serve on an acting basis in the role, which is largely administrative.
Phelan is the latest high-ranking military leader to leave the administration in recent months. His departure comes amid the US-Israel war with Iran and the continued US blockade of the Strait of Hormuz.
The Navy has not provided a reason. His exit came after tension within the American leadership over issues around shipbuilding, according to unconfirmed reports in US media.
"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."
It comes just weeks after US Defense Secretary Pete Hegseth asked Army Chief of Staff Randy George to step down from his post.
Two other Army officials, Gen David Hodne and Maj Gen William Green, have also been removed from their roles recently.
Since entering the Pentagon, Hegseth has fired more than a dozen senior military officers, including the chief of naval operations and the Air Force's vice chief of staff.
Phelan was ousted from his job after he, too, ended up clashing with Hegseth over the implementation of Trump's shipbuilding initiative, according to sources who spoke to multiple news outlets.
The secretary's role is largely administrative and includes formulating policies, recruiting, training and equipping the Navy, as well as overseeing budgeting and logistics like construction, and repair of naval ships and facilities.
Phelan, a civilian who had not previously served in the military, was sworn in as Secretary of the Navy in March 2025 after being nominated by President Donald Trump in 2024. The businessman was a major donor to Trump's campaign.
The two appeared alongside one another at Mar-a-Lago last December when Trump announced that the US would commission a new series of heavily armed Navy "battleships" named after himself - part of a revamped "Golden Fleet" which Phelan supported.
Andrew Peek, a former State Department deputy assistant secretary, told the BBC that the president had been clear that he wanted to expand the country's merchant and civilian fleet.
"Eventually, somebody was going to take the fall for the lack of movement on that. I would bet that's about 30% of this," Peek said.
"The other 70% - Phelan's replacement is very well known to the MAGA base, I would bet it's a simple replacement with someone he likes and trusts better," he added.
Phelan's replacement, Cao, became undersecretary in October 2025 and is a 25-year Navy veteran.
He ran an unsuccessful campaign for the US Senate in Virginia in 2024, endorsed by Trump, against incumbent Democratic Senator Tim Kaine. During a campaign debate, he criticized the military's diversity, equity and inclusion initiatives.
Speaking about Navy recruiting during the debate, Cao said: "What we need is alpha males and alpha females who are going to rip out their own guts, eat them and ask for seconds. Those are the young men and women that are going to win wars," the AP reported.
The Navy's change in leadership comes as Trump said the US blockade of Iranian ports would continue amid a ceasefire in the war. Clashes have continued in the Strait of Hormuz, a vital global shipping route that supplies much of the globe's oil, with Iran announcing that it had "seized" two ships in the strait.
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".
Mohammad Bagher Ghalibaf, Iran's chief negotiator in talks with the US, said on Wednesday that it is "not possible" for the Strait of Hormuz to be re-opened due to "the blatant violations of the ceasefire" by the US and Israel.
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