Pope John Paul II has added his voice to international condemnations of Cuba's crackdown on dissidents, including the execution of three hijackers.
The Pope is a long-time opponent of the death penalty
In a letter to Cuban President Fidel Castro, released by the Vatican, the pontiff expressed his "deep pain"
at the executions, and appealed for clemency for 75 imprisoned dissidents.
On Friday, Mr Castro said the death penalty had been intended to deter further hijackings.
The men had seized a ferry and tried to force the crew to go to the United States.
Eleven people took part in the attempted hijack, in which nobody was hurt.
Mr Castro accused the United States of seeking to provoke a mass exodus of Cubans from their homeland.
The executions ended a three-year moratorium on capital punishment in Cuba, and were condemned by governments and human rights groups around the world.
The hijacking eventually ended with no one hurt
The pope's appeal was dated 13 April, but released only on Saturday by the
Vatican, through its secretary of state, Cardinal Angelo Sodano.
The message asked President Castro for "a significant gesture of clemency toward those convicted".
"I am sure that you share also share with me the conviction that only a sincere and constructive confrontation between the citizens and the civil authorities can guarantee the promotion of a modern and democratic Cuba," the pope said.
John-Paul II, who became the first pontiff to visit Cuba in 1998, is a staunch opponent of the death penalty.
In a lengthy speech on Friday, Mr Castro accused America of trying to destabilise Cuba and provide an excuse for military intervention
He said the 75 Cuban dissidents sentenced to prison terms of up to 28 years were mercenaries in the pay of the enemy.