Doral, Florida - The US admiral responsible for overseeing a major military buildup in the Caribbean and controversial strikes on alleged drug-smuggling boats stepped down on Friday just a year into his tenure.

Admiral Alvin Holsey announced in mid-October that he would leave his position as head of US Southern Command, which is responsible for American forces operating in Central and South America.

Holsey had reportedly expressed concerns about the boat strikes, but neither he nor Pentagon chief Pete Hegseth has publicly provided a reason for his early departure.

In his remarks during a ceremony marking his relinquishment of command, the admiral emphasized the importance of supporting nations that believe in democracy and human rights.

"We must always be there for like-minded partners, like-minded nations who share our values – democracy, rule of law, and human rights," Holsey said.

The US has amassed a huge flotilla of warships in the Caribbean as part of what Washington bills as counter-narcotics efforts, and has since September carried out strikes targeting alleged drug-smuggling vessels that have left nearly 90 people dead.

Trump's administration insists it is effectively at war with alleged "narco-terrorists," but experts say the strikes on the boats amount to extrajudicial killings even if they target known traffickers.

The first strike, which took place on September 2, is especially controversial, as two survivors of the initial attack were killed in a subsequent hit.

Regional tensions have flared as a result of the strikes and the military buildup, with Venezuela's leftist leader Nicolas Maduro accusing Washington of using drug trafficking as a pretext for regime change in Caracas.

Now responsible for both the campaign of boat strikes and efforts to pressure Maduro is Air Force Lieutenant General Evan Pettus, who said he was "humbled" to take on the role in an acting capacity.

Since beginning his second White House term in January, President Donald Trump has overseen a purge of top military officers, including the chairman of the Joint Chiefs of Staff, General Charles "CQ" Brown, whom he fired without explanation in February.

Hegseth has insisted the president is simply choosing the leaders he wants, but Democratic lawmakers have raised concerns about the potential politicization of the traditionally neutral US military.