Cuba has for the first time attacked the use of Guantanamo Bay as a centre for detaining people the US suspects of links to the Taleban and al-Qaeda.
The Guantanamo Bay centre is in south-east Cuba
A Cuban parliament statement called the leased US facility a "concentration camp" and said inmates were subjected to "indescribable humiliations".
The comments add to growing concern over the rights of those being held.
Over 600 men detained in Afghanistan, Pakistan and elsewhere on suspicion of terrorism are being held there.
The prisoners are "totally isolated, without the possibility of communicating with their
families or access to appropriate legal defence," the Cuban statement said.
"They commit very serious attacks on human dignity, in an
atmosphere of hysteria and fear nurtured by North America's
far-right," it continued.
The Guantanamo Bay base is leased under an agreement signed before Fidel Castro took power in 1959.
The Cuban leader routinely describes that agreement as illegal and pointedly refuses to cash the cheques for rental which the US sends every year.
No legal rights
Until now Cuba has not been overtly critical of the US decision to hold terror suspects at the base, says the BBC's Steven Gibbs in Havana.
Indeed it surprised many observers by offering logistical and medical assistance, our correspondent says.
The US maintains that the prisoners are being well treated.
The Bush administration has said the men have no rights to the American legal system because they are being held in a foreign land.
As the US government has classified the men as "enemy combatants", rather than prisoners of war, they are not given all the protections of the Geneva Conventions.
The prisoners have so far not been charged.