The 10 aircraft will join US warships already present in the southern Caribbean as Trump steps up pressure on Venezuelan President Nicolas Maduro, whom the United States accuses of leading a drug cartel.

The standoff has grown in recent days as the Pentagon said two Venezuelan military planes flew near a US Navy vessel in international waters Thursday in a "highly provocative" move.

Asked Friday what steps he would take if there were further incidents, Trump said: "If they do put us in a dangerous position, they'll be shot down."

US forces on Tuesday blew up an alleged drug boat in the Caribbean that Trump said belonged to Tren de Aragua, a Venezuelan criminal organization he tied to Maduro, killing 11 people.

The high-tech F-35 jets are being deployed to an airfield in Puerto Rico, a US Caribbean island territory of more than three million people, US sources familiar with the matter told AFP Friday on condition of anonymity.

Maduro -- a leftist firebrand whose last election in 2024 was seen by Washington as illegitimate -- has denounced the US build-up as "the greatest threat our continent has seen in the last 100 years."

Declaring his country prepared for "armed struggle in defense of the national territory," he has mobilized Venezuela's military, which numbers around 340,000, and reservists, which he claims exceed eight million.

- 'Highly provocative' -

"If Venezuela were attacked, it would immediately enter a period of armed struggle," Maduro told foreign correspondents.

White House Deputy Chief of Staff Stephen Miller took aim at Maduro on Friday, describing him as an "indicted drug trafficker" and saying Venezuela is being run by a "drug cartel, a narcotrafficking organization."

Tuesday's deadly attack on what Washington said was a drug-carrying boat was a major escalation, as well as an unusual use of the US military for what has historically been a law enforcement issue.

There are currently eight US Navy vessels involved in counter-narcotics efforts in Latin America: three amphibious assault ships, two destroyers, a cruiser and a littoral combat ship in the Caribbean, and one destroyer in the eastern Pacific, a US defense official said this week.

The Department of Defense -- which Trump rebranded Friday as the "Department of War" -- said two "Maduro regime" aircraft flew near a US vessel Thursday.

"This highly provocative move was designed to interfere with our counter narco-terror operations," it said on X. It did not give further details.

Venezuela has 15 F-16 fighter jets purchased from the United States in the 1980s, plus a number of Russian fighters and helicopters.

During a trip to Latin America this week, Secretary of State Marco Rubio defended the new aggressive approach towards what Washington calls "narcoterrorist" groups.

"What will stop them is when you blow them up, when you get rid of them," Rubio said Wednesday in Mexico.

"If you're on a boat full of cocaine or fentanyl headed to the United States, you're an immediate threat to the United States."

Caracas accused Washington of committing extrajudicial killings in Tuesday's attack.