Hegseth was accompanied by the top US military officer, General Dan Caine, and the two of them were welcomed by Jenniffer Gonzalez-Colon, the territory's governor, who announced the visit in a post on X.

She also thanked President Donald Trump "and his Administration for recognizing the strategic value Puerto Rico has to the national security of the United States and the fight against drug cartels in our hemisphere, perpetuated by narco-dictator Nicolas Maduro."

The United States alleges that leftist Venezuelan leader Maduro heads a cocaine trafficking cartel and recently doubled its bounty to $50 million in exchange for his capture to face drug charges.

A Pentagon official confirmed Hegseth had traveled to Puerto Rico, but provided no further details.

The visit comes around a week after the United States carried out a strike on an alleged drug-smuggling boat coming from Venezuela, an action that Trump said left 11 purported members of the Tren de Aragua gang dead.

Tensions between Washington and Caracas subsequently soared after the Pentagon accused Venezuela of buzzing its ships in the Caribbean following the deadly strike, while Maduro has also denounced the buildup of US military assets in the region.

There are eight US Navy ships involved in counter-narcotics efforts in Latin America -- seven in the Caribbean and one in the Pacific -- while Washington is also dispatching 10 high-tech F-35 jets to Puerto Rico.

Trump vowed Friday to shoot down Venezuelan military jets if they pose a danger to US forces, but Maduro subsequently called for dialogue with Washington.

Drug-smuggling vessels are usually interdicted and their crews arrested once they are identified, making the US strike on the alleged traffickers an extremely rare event.

Trump's administration designated Tren de Aragua as a terror organization earlier this year, and the use of deadly force against the group's alleged members without due process echoes US actions against purported militants during its years-long "War on Terror."

US officials, including Hegseth, have said that strikes targeting drug cartels will continue.