US President Donald Trump has ordered a troop buildup in the Caribbean as part of an anti-drug trafficking initiative, but speculation has abounded that Washington may be contemplating military intervention against Venezuelan strongman Nicolas Maduro.

The US Southern Command (SOUTHCOM), which oversees American forces in Latin America and the Caribbean, had previously said that the USS Gerald R. Ford Carrier Strike Group had entered its area of responsibility.

On Sunday, it announced in a statement that the strike group had entered the Caribbean Sea, saying the move follows Trump's "directive to dismantle Transnational Criminal Organizations and counter narco-terrorism in defense of the Homeland."

The strike group includes the most advanced US aircraft carrier, two guided-missile destroyers, and other support vessels and aircraft.

It joins several warships already in the Caribbean, with the deployment dubbed "Operation Southern Spear."

Since launching the anti-trafficking military campaign in September, US forces have killed at least 80 people accused of ferrying drugs in international waters, according to an AFP tally of publicly released figures.

The United States has released no details to back up its claims that the people targeted -- in both the Caribbean and eastern Pacific -- in the 20 strikes were actually traffickers.

Experts say the deaths amount to extrajudicial killings even if they target known traffickers.

Caracas meanwhile views the military buildup as an explicit threat.

The United States does not recognize Maduro as Venezuela's legitimate president and has issued a $50 million bounty for his capture to face charges of leading a drug cartel.

Amid reports that Trump held meetings with military advisors on potential options for Venezuela, the US president on Friday told reporters he had "sort of" made up his mind on the issue.

"I can't tell you what it is, but we made a lot of progress with Venezuela in terms of stopping drugs from pouring in," he said aboard Air Force One.

He had previously said in a CBS News interview that he doubted the United States would go to war with Venezuela, but that he believed Maduro's days were numbered.

The US military has also been stepping up its presence in Trinidad and Tobago, an archipelago just off Venezuela's coast.

US and Trinidadian forces were due Sunday to begin joint training exercises for the second time in less than a month. On Saturday, Maduro blasted the drills as "irresponsible."