US forces have seized an oil tanker off the coast of Venezuela, President Donald Trump said, marking a sharp escalation in Washington's pressure campaign against Nicolás Maduro's government.

We have just seized a tanker on the coast of Venezuela - a large tanker, very large, the largest one ever seized actually, Trump told reporters at the White House.

Releasing a video of the seizure, Attorney General Pam Bondi described the vessel as a crude oil tanker used to transport sanctioned oil from Venezuela and Iran.

Caracas swiftly denounced the action, calling it an act of international piracy. Earlier, President Maduro declared that Venezuela would never become an oil colony.

The Trump administration accuses Venezuela of funnelling narcotics into the US and has intensified its efforts to pressure President Maduro in recent months. Venezuela, home to some of the world's largest proven oil reserves, has, in turn, accused Washington of seeking to take its oil.

Oil prices inched higher as news of the seizure stoked short-term supply concerns. Analysts warn the move could threaten shippers and further disrupt Venezuela's oil exports.

US Attorney General Pam Bondi stated that the seizure was coordinated by multiple US agencies. The tanker had been sanctioned by the US for its involvement in an illicit oil shipping network.

The Venezuelan government condemned the seizure as a grave international crime, insisting it would not allow any foreign power to deprive its people of their natural resources. Maduro responded to public sentiment against war by singing a well-known song, urging peace instead.

This operation is part of increased US military presence in the Caribbean, leading to speculation about further military actions.