Thirty Cuban dissidents are being held by US authorities at the Guantanamo Bay naval base, a Cuban exile leader says.
The US says about 600 detainees are being held in Guantanamo Bay
The head of the Miami-based Democracy Movement, Ramon Saul Sanchez, told the BBC the dissidents fled Cuba last year after the arrest of 75 activists.
They were stopped by US vessels and had been held secretly for the past year - even though they had been promised passage to a third country, he said.
The US says its Cuba base holds nearly 600 prisoners from the "war on terror".
There is no reported comment from US officials on the allegations.
'Women and children'
The 30 dissidents reportedly left Cuba after a March 2003
round-up of opponents of the government of President Fidel Castro.
Seventy-five activists were imprisoned for up to 28 years last April.
The Guantanamo group is said to include four women and four children.
Mr Sanchez told the BBC that Washington had threatened to hand over the dissidents to the Cuban authorities if they talked to the press.
Human rights groups have criticised the facility and the
treatment of detainees.
The US government has released dozens of the prisoners after concluding that they did not pose a threat.
"If we are in a time when terrorists are being released
from Guantanamo because they have found out that they are no harm... why are we keeping human rights
activists incarcerated?" Mr Sanchez said.