Reuters- Human rights group Amnesty International urged Cuba to release political prisoners and take other measures to end what it called a "climate of fear" for government opponents, in a report issued on Wednesday.

"The release of all prisoners of conscience and the end of harassment of dissidents are measures that the Cuban government must take immediately and unconditionally," Kerrie Howard, the group's Deputy Americas Director, said in a statement that accompanied the report on Cuba's limits to free expression.

"It is clear that the U.S. embargo has had a negative impact on the country, but it is frankly a lame excuse for violating the rights of the Cuban people," Howard said.

Amnesty International says Cuba has 53 "prisoners of conscience." The independent Cuban Commission on Human Rights says the island has about 190 political prisoners locked away, including the 53 cited by Amnesty.

Cuba views dissidents as mercenaries working for the United States and other enemies to undermine the government.

It has said control of government opponents will end when the United States stops promoting political change in Cuba.

The trade embargo was imposed 48 years ago after Fidel Castro took power in Cuba in a 1959 revolution and remains in place, never having achieved its aim of toppling the government.

Amnesty International said Cuban laws restrict freedom of speech and stifle dissent, and are capriciously interpreted by courts serving the desires of the state.

It said the government "has a virtual monopoly on media while demanding that all journalists join the national journalists' association, which is in turn controlled by the (ruling) Communist Party."

The government blocks access to opposition Internet sites, the group said.

Cuba must "dismantle the repressive machinery built up over decades and implement the reforms needed to make human rights a reality for all Cubans," Howard said.

Cuba came under international criticism after the February death of dissident hunger striker Orlando Zapata Tamayo and in recent weeks has slightly relaxed its policies toward dissidents.

One political prisoner was released earlier this month and 12 other moved to jails closer to their families following a meeting between President Raul Castro and Cardinal Jaime Ortega, head of the Cuban Catholic Church.

Church officials have said they are hoping for the release of more prisoners.