Dissident groups in Cuba say harassment and detentions by police have recently increased as part of a new tactic by the authorities.
Elizardo Sanchez says the political mood has hardened recently
Rights activist Elizardo Sanchez said he believed the aim was to deter dissidents from marking International Human Rights Day on 10 December.
The Cuban government says dissidents are mercenaries funded by the US.
Church leaders meanwhile say officials have apologised for arresting several people at a church on Tuesday.
The Roman Catholic archbishop in the eastern city of Santiago de Cuba, Dionisio Garcia Ibanez, told the BBC that all 11 people had been released.
He said he had met communist party officials who described the incident as regrettable.
The arrests took place after a group of dissidents marched to the church to protest about the arrest of another government opponent.
The Cuban authorities have not made any public statement about the incident.
For years, Cuba was officially atheist, but ties with the Vatican improved following Pope John Paul II's visit to the island in 1998.
In July this year, Roman Catholic bishops from across Latin America met in the Cuban capital, Havana.
The number of political prisoners in Cuba has fallen since Raul Castro, brother of President Fidel Castro, took over as acting president on 31 July 2006, according to the Cuban Commission for Human Rights and Reconciliation.
But the group, illegal but tolerated by the authorities, says there has been a marked increase in police activity in recent weeks.
Its head, Elizardo Sanchez, said the authorities were using a new tactic which he called "preventative repression".
"For example, if a group is going to meet in a house or park, they will detain people so they can't get there," Mr Sanchez said.
"Before, it wasn't so subtle, just pure hard repression, straight to prison. Now the authorities are being more careful."
The Cuban government has long said there are no political prisoners in Cuba, and that those it jails are mercenaries paid by the US government to undermine the Cuban Revolution.