Forces deployed for what Washington called an anti-drug operation have destroyed at least two Venezuelan boats carrying a combined 14 people allegedly transporting drugs across the Caribbean this month, a move slammed as "extrajudicial execution" by UN experts.

The strikes and a deployment of US warships in the region has raised fears of an invasion in Venezuela, whose President Nicolas Maduro Washington accuses of being a cartel leader.

"There will be air defense deployments with armed drones, surveillance drones, submarine drones... We are going to implement electronic warfare actions," Defense Minister Vladimir Padrino Lopez said Wednesday, citing the "threatening, vulgar voice" of the United States.

Public television showed images of amphibious vessels and warships deployed off La Orchila, where Venezuela has a military base.

The armed forces said the three-day exercise will involve 12 ships, 22 aircraft and 20 small boats from the "Special Naval Militia."

La Orchila island is close to the area where the United States intercepted and held a Venezuelan fishing vessel for eight hours over the weekend.

Venezuela has urged an investigation of a US strike on an alleged drug boat early this month that killed 11 people -- one of three Venezuelan vessels US President Donald Trump said his country had "knocked off" without providing details.

Maduro, whose last two elections the US and many other countries did not recognize, has vowed Caracas would defend itself against what he labeled US "aggression" against his country.