Diplomatic sources in Havana said "considerable progress" towards the two visits had been made during talks in the Cuban capital at the weekend between Cuban officials and the Vatican's "Foreign Minister", the French Archbishop Jean-Louis Tauran.
The Archbishop arrived on Friday with the general aim of strengthening relations with President Castro's long-time Communist and atheist regime but with finalising the two visits his priority, the sources said.
Castro, who purged the Catholic Church in the early years after his 1959 revolution but has gradually eased the restrictions, is expected to meet the Pope in mid-November while in Rome for a meeting of the UN Food and Agriculture Organisation.
The pontiff, who took part in a religious service in St Peter's Basilica yesterday, for the first time since his appendix was removed earlier this month, is likely to visit the island next year, the sources said.
"It's going well," Archbishop Tauran told reporters after separate weekend meetings with the Cuban Foreign Minister, Roberto Robaina, and the speaker of Castro's rubber-stamp parliament, Ricardo Alarcon. Both men are key aides to the Cuban leader and among those tipped to succeed him if he ever stands aside.
"Now, we have to resume the custom of meeting with greater frequency," the Vatican envoy said.
The Pope, who participated only in the first 70 minutes of yesterday's three-hour service and later delivered his regular blessing in a firm voice to thousands in St. Peter's Square, is known to be eager to visit one of three Latin American nations he has never seen. The others are Guyana and Surinam.
Cuba was strongly Catholic until Mr Castro's nationalist guerrillas overthrew the dictator Fulgencio Batista and quickly fell under the Marxist influence of the Soviet Union, with an officially atheist regime.
The last senior Vatican envoy who attempted to strengthen relations was the then "Foreign Minister" Agustin Casaroli, in 1974. He had little success.
As Mr Castro eased restrictions on religion, the Pope appeared set to visit the island in 1989 but called it off at the last moment after Mr Castro said the pontiff was seeking too many concessions.
Following the collapse of the Soviet Union, Mr Castro largely turned a blind eye to religious worship, and Catholics increasingly returned to churches. The Cuban Cardinal Jaime Ortega, appointed by Pope John Paul, has played a key role in improving relations and is said to have been the driving force between the two proposed visits.
Vatican sources said the Pope, who has condemned the long-standing US embargo on Cuba as inhumane, did not want a mere "photo opportunity" with Castro, but would seek major concessions, including a greater role for the church in education.
The Cuban leader is likely to use the visit to back his campaign against the three-decade US economic embargo. Before his weekend meetings, Archbishop Tauran made a point of rejecting the so-called Helms-Burton law, signed by President Bill Clinton earlier this year, which lays down tight restrictions on foreign companies operating in Cuba. "We do not like the politics of empires," the Vatican envoy said.Reuse content