Cuban President Raul Castro says that Pope Francis' action may push him back to the Church.
"If the Pope keeps going the way he's going, I'll come back to the Catholic church," Castro said at a news conference at the office of the Italian prime minister, Matteo Renzi, whom he met after talks at the Vatican on May 10.
The communist leader had stopped in Rome after attending Russia's World War Two Victory Day parade in Moscow.
"When the Pope goes to Cuba in September, I promise to go to all his masses, and with satisfaction," the Guardian newspaper reported.
The Cuban president praised Pope Francis for helping broker a restoration of relations between Cuba and the United States, announced in December.
At the end of his Vatican audience, Castro said he had thanked the Pope for his contribution for the historic rapprochement.
"I am very happy. I have come here to thank him for what he has done to begin solving the problems of the United States and Cuba," said Castro.
The Vatican engaged in secret negotiations to put an end to more than five decades of hostilities were carried out inside the Vatican.
Francis greeted Castro in his native Spanish saying, "Bienvenido!" when he welcomed Castro to his studio near the Vatican's public audience hall for nearly an hour of private talks that lasted nearly an hour.
Castro, the brother of Fidel, the leader who brought the Communists to power in Cuba in a 1959 revolution, praised Francis.
Although the Catholic Church has continued ties with Havana since the 1959 revolution, they have sometimes been strained.
Cuba's State-run newspaper Granma did not mention Castro's comments about returning to the Church when it reported the meeting with Pope Francis on its website, the BBC reported and commented, "A reflection, perhaps, of how surprising it is for Cubans to hear Mr. Castro make such comments, whether tongue-in-cheek or not."