Vietnam has revoked the visas of three representatives of the Roman Catholic church seeking to hold talks about the possible beatification of a late cardinal who was forced into exile, church officials said on Tuesday.

The delegation was set to arrive this Friday and planned to discuss the late Cardinal Francois Xavier Nguyen Van Thuan, who was appointed deputy archbishop of Saigon days before the South Vietnamese capital fell to the communist North in 1975.

The delegation was sent by the diocese of Rome, which is considering pushing ahead with a cause for the beatification of the cardinal, a controversial issue in the communist-run country. Beatification is the last official step before possible sainthood.

A Vatican official, who has followed the case but spoke on condition of anonymity because of the sensitivity, said the three were traveling on tourist visas. He said he had no additional information.

Thuan was a nephew of Ngo Dinh Diem, president of US-backed South Vietnam who was assassinated in 1963 during the Vietnam War.

In 1991, Thuan was forced into exile in Rome after spending 13 years in a communist re-education camp. He died in 2002, one year after being appointed cardinal.

Vietnam and the Vatican held talks last month in Hanoi, but the two sides did not reach a breakthrough in establishing formal ties.

There are six million Roman Catholics in Vietnam, the second largest Catholic community in Southeast Asia after the Philippines. However, tensions have existed for decades between Catholics and the Hanoi government over church property seized by the Communists and other issues.

Pope Benedict XVI appointed Archbishop Leopoldo Girelli in January 2011 as his special, nonresident envoy in what was seen as a step in improving relations.