But military experts take a dim view of Venezuela's combat readiness, saying years of crisis have made a paper tiger of its armed forces.

President Nicolas Maduro has accused the United States of pursuing regime change in Venezuela under the guise of an operation to combat drug trafficking.

Washington, which accuses Maduro of heading a drug cartel, has dispatched eight warships and a nuclear-powered submarine to the southern Caribbean and sent 10 fighter jets to nearby Puerto Rico in the biggest naval build-up in the region in years.

President Donald Trump claims US forces have blown up three Venezuelan drug boats, killing at least 14 people he described as "narco-terrorists" in strikes condemned as "extrajudicial execution" by UN experts.

"It's an undeclared war," Defense Minister Vladimir Padrino Lopez said Friday, rallying the troops during war games on Venezuela's Caribbean island of La Orchila.

- 'Waste of time and money' -

Some 2,500 troops, 12 naval vessels and 22 aircraft were deployed to island for three days of exercises.

They were backed by 20 wooden fishing boats carrying members of a civilian militia that Maduro has put at the center of his battle plan.

TV images showed paratroopers landing on the island, Russian Sukhoi fighter jets combing the skies, and troops in amphibious Chinese-made tanks with their cannons pointed skyward.

Russian-made artillery pieces and anti-aircraft radars were also on display.

"Venezuela must remain impregnable," Interior Minister Diosdado Cabello said.

Several analysts poured scorn, however, on the idea that Venezuela could take on the world's biggest military power.

Experts have pointed to an ill-disciplined force and outdated arsenal as an effect of the political crisis and economic collapse that has seen an 80 percent drop in Venezuela's GDP under Maduro.

- 'An easy target' -

Political and military analyst Hernan Lugo-Galicia told AFP that concentrating so much of its force on La Orchila -- near where the United States intercepted and held a Venezuelan fishing vessel for eight hours last week -- was a strategic mistake on Venezuela's part.

"It's an easy target. A maritime blockade with air support would eliminate them instantly," he said.

Exiled former Air Force commander Raynell Martinez said the drills were merely a show, aimed at making Venezuelans believe the armed forces were fully operational.

A retired general and former political prisoner, who refused to be identified, agreed.

"It's to convey that they (Venezuela) are not afraid of confronting anyone," he told AFP, dismissing the exercises as a "waste of time and money" held in an environment "entirely different from the mainland" that would be the likely target of any US invasion.

- Militia size in doubt -

The propaganda war is being fought on both sides of the Caribbean.

Trump has shared grainy aerial footage of two boats being blown up and the military has released footage of destroyers, planes and troops in the Caribbean.

The International Institute for Strategic Studies estimates that Venezuela's armed forces comprise 123,000 personnel, with an additional 220,000 volunteer militia members made up of Maduro loyalists.

Experts believe the numbers are much lower.

Venezuela has vowed to defend itself against Washington's aggression, and thousands of militia members have turned out for military-style training in recent days.

On Saturday, Venezuelan troops will provide weapons training to civilians in the capital.