The Vatican issued a detailed schedule for the Aug. 31-Sept. 4 trip, a sign that the visit could now be called off only for extreme reasons.

Francis, 86, who spent nine days in hospital after surgery for an abdominal hernia last month, is due to visit Portugal from Aug. 2 to 4. He is resting for the month of July, the Vatican's customary holiday month.

Francis will spend all of his time in Mongolia in Ulaanbaatar, capital of the vast country with only about 1,300 Catholics, fewer than most parish churches in many places.

To allow him to rest after a night flight of more than nine hours and 8,278 km (5,144 miles) he will have no public activities on the first day apart from a brief official welcome at the airport named after Genghis Khan, who founded the Mongol Empire in the 13th century.

During the trip he will meet with authorities, diplomats, bishops, priests, missionaries, members of others religions and also say a Mass for the tiny Catholic community in the Steppe Arena, an indoor ice hockey rink.

The country of about 3.3 million people is strategically significant for the Roman Catholic Church because of its proximity to China, where the Vatican is trying to improve the situation of Catholics.

Mongolia, which was part of China until 1921, has good relations with Beijing and diplomats say it could be used as an intermediary with China.

Last year, Francis named Archbishop Giorgio Marengo, an Italian, the first cardinal to be based in Mongolia, where he is the Catholic Church's administrator.

Visiting places where Catholics are a minority is part of Francis' policy of drawing attention to people and problems in what he has called the peripheries of society and of the world.

He still has not visited most of the capitals of Western Europe.

According to the U.S. State Department, about 60% of Mongolians identify as religious. Among those, 87.1% are Buddhist, 5.4% Muslim, 4.2% Shamanist, 2.2% Christian and 1.1% followers of other religions.