The Cuban Government has for the first time confirmed that it has sentenced 75 political dissidents to long prison terms.
The crackdown came despite improving foreign ties
Foreign Minister Felipe Perez Roque said that Cuba was acting to protect its independence from a US-funded conspiracy to undermine the government of Fidel Castro.
The convictions and sentences of up to 28 years have provoked worldwide criticism.
But Mr Perez Roque said the dissidents were part of a plot in which the US Government was attempting to create and fund a political opposition in Cuba.
He objected to descriptions of the accused as independent journalists and economists, calling them mercenaries.
As evidence, the foreign minister alleged that large sums of cash had been found in many of their houses.
Families keep vigil outside the court in Havana
He also released the first videotape from the closed trials, which have been held throughout Cuba over the last week.
In one, a nervous looking dissident is seen apparently confessing that he was working for the United States.
Cuba appears unconcerned by the barrage of criticism the trials have prompted from governments and human rights groups around the world.
Mr Perez Roque said the complaints were made by those who did not understand Cuba's struggle for independence.
US 'won't let up'
A White House spokesman said the crackdown on dissent was proof that President Castro's government remained a "totalitarian blight" on the region.
The US House of Representatives unanimously passed a bill on Tuesday condemning the dissidents' arrests and the harsh sentencing of many of them.
"We are not going to reverse our policy of helping the dissidents," said national security spokesman Michael Anton.
The EU Commission also called for the immediate release of the dissidents.
Human rights groups worldwide have condemned the trials.