About 100,000 Cuban regular troops are also taking part in the "Bastion 2004" exercises which started Monday, officials said.

"The only way to stop aggression is to make it abundantly clear that, in this case, Cuba will become from one end to the other an enormous wasp's nest that no aggressor, however powerful, will be able to overcome," Defense Minister Raul Castro said Monday.

"In the end, (the aggressor) will have to withdraw, bloodied and defeated, because this would be a war of all of the people," Castro, a younger brother of President Fidel Castro, warned.

Trucks towing armored cars and officers armed for battle were mobilized on the streets of Havana early Tuesday.

Massive underground shelters in the Havana area where planes, tanks and heavy artillery are housed were opened to combat troops.

The United States on Monday rejected assertions that it planned an invasion. US State Department spokesman Richard Boucher said: "We don't think there is any justification, or any particular foundation for this kind of charge."

"The United States has repeatedly called for a peaceful transition to democracy in Cuba. We think that's what the Cuban people deserve, and we think they deserve it in a peaceful fashion," Boucher said.

These "exercises are just, I would say, one or more of the many things that the Cuban government does to try to distract people from the problems that they face in their daily lives," Boucher said.

General Leonardo Andollo said Sunday that MiG-29 jets, anti-aircraft batteries were to be deployed during the weeklong exercises.

Senior military and Communist government officials warned that the US administration of President George W. Bush should take note of the island's war footing.

"The determination of the US administration to destroy the (Cuban) revolution however they can, including militarily, determines the necessity of conducting these exercises," Andollo, the deputy chief of Cuba's Armed Revolutionary Forces (FAR), said.

His comments come days after Raul Castro warned Washington should closely observe Cuba's military prowess and civil defenses during the manoeuvres, billed as the country's biggest since 1986.

Officials said the exercises would also involve several million civilians who will participate in two days of civil defense exercises, including a simulated aerial assault.

Raul Castro said last week the exercises had been planned in part so Washington "does not commit the errors it committed in Vietnam and that it is now committing in Iraq. So that they do not underestimate our people, who are united and more powerful than those in Iraq."

The communist-run island sits some 90 miles (145 kilometers) off the coast of Florida.

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