Press watchdog IPI on Sunday welcomed Cuba's decision to release a first batch of political prisoners, but insisted that all jailed dissidents must be freed.

"We call on Cuba to immediately release all the dissidents, including journalists, who remain in prison," David Dadge, director of the Vienna-based International Press Institute, said in a statement.

Communist Cuba on Saturday began releasing a group of ailing political prisoners as part of a landmark church-brokered deal to free 52 dissidents, relatives of three freed inmates told AFP.

All 52 were part of a group of 75 dissidents rounded up in 2003 and sentenced to jail terms of between six and 28 years.

Among them were 29 journalists, said IPI.

"While we welcome this long overdue move by Cuba to release political prisoners detained in the infamous Black Spring crackdown, it is far from enough," said Dadge.

Three journalists, Jose Luis Garcia Paneque, Pablo Pancheco and Lester Gonzalez, were believed to be part of the first group of freed dissidents, according to IPI.

However, Omar Rodriguez Saludes, the director of Nueva Prensa Cubana, an independent news agency in Havana, was expected to remain in prison.

He was sentenced to 27 years in prison in 2003 -- the longest sentence among all 29 journalists, said IPI.

Spain, which helped broker the deal between the Cuban government and the church, has said it is willing to receive all the prisoners after their release.