Washington accuses Maduro of heading a drug cartel and has deployed significant military assets -- including stealth warplanes and several US Navy ships -- as part of what it says are counter-narcotics efforts in the Caribbean.

Maduro, an authoritarian socialist who is widely accused of stealing elections last year, says Washington is plotting regime change.

Trump has indicated that he authorized covert CIA operations against Venezuela, without offering specifics.

Maduro has responded to the big US military operation by ordering exercises around the country and positions soldiers at the borders.

"Today we have completed all the country's integrated defense zones," Maduro said in a recording released on Telegram.

He also announced a new military exercise he called Independence 200.

Many such exercises are carried out at night and do not conclude with new, permanent positioning of military forces.

State TV aired footage of soldiers leaving barracks.

Police, civil protection staff and civilian militia members have also taken part in Venezuela's exercises amid tensions with the United States.

US forces in the Caribbean have now attacked at least six vessels that Washington said were taking drugs from the Venezuela toward the United States, killing at least 27 people.