Fidel Castro has said he will die "with a gun in my hand", in a defiant speech to anti-globalisation activists.
Castro's speech went on for five hours
In a five-hour speech in the Cuban capital, Havana, the communist leader said his country was ready to repel an invasion from the United States.
"These idiots had better not believe we're wasting our time... This country will never give up. It will never lay down its weapons," he said.
He accused the Bush administration of plotting with Miami exiles to kill him.
President Castro was addressing a gathering of about 1,000 international activists against free trade - and in particular the US-backed Free Trade Area of the Americas (FTAA).
"El Comandante", as Mr Castro is best known to his compatriots, said he did not want a war against "Yanquee imperialism".
But he alleged that US President George Bush had committed himself to trying to kill him and overthrow his government.
'Dead man' fighting
"We knew that Mr Bush had made a commitment with the mafia [Cuban exiles] of the Cuban-American Foundation to kill me. I accuse him of this," he said.
"This dead man can still talk. This dead man can make plans.
This dead man ... is not dead yet.
"With a gun in my hand, I don't care how I die, but I'm confident that if they invade us, I will go down fighting," Mr Castro said to tumultuous applause from the audience, which included Andean Indians, landless Brazilians, and Canadian postal workers.
Mr Castro is known to have survived several CIA plots to assassinate him during the 1960s.
But many Cubans now fear that Washington, frustrated by the failure of a 40-year embargo to bring down Mr Castro, may be planning an imminent land invasion.
Some 130,000 "committees for the defence of the revolution" and other local organisations have been told to step up their vigilance.
President Bush has set up a special committee to monitor events in Cuba and "plan for the happy day when Castro's regime is no more".
Earlier this year, Bush administration officials also accused Cuba of trying to destabilise other Latin American states.