Thousands of pilgrims took part in an open-air mass in southern Italy, to mark the official opening of the public display of the body of Padre Pio. The hugely popular mystic monk, declared a saint in 2002, died 40 years ago. Sabina Castelfranco reports from Rome.

The body of Padre Pio, an Italian saint, laying in repose inside a crystal casket in the crypt of the church of Santa Maria delle Grazie in San Giovanni Rotondo, Italy, 24 Apr 2008

From early in the morning, pilgrims gathered at the new church in San Giovanni Rotondo, designed by the internationally renowned Italian architect Renzo Piano. They turned out in the thousands to attend an open-air mass marking the official opening of public viewing of Saint Pio da Pietralcina.

Attending were many Capuchin monks and the two people who received the miracles from Padre Pio that led to his canonization in 2002.

Portuguese Cardinal Jose Saraiva Martins, prefect of the Vatican Congregation for the Causes of Saints, celebrated the mass.

The cardinal said that from today the body of Padre Pio that for 50 years bore the gift of the stigmata, the bleeding wounds of the crucified Christ, would be on display for the veneration of the faithful.

This year marks the 40th anniversary of the death of the hugely popular saint. Padre Pio was a monk who continues to inspire millions of followers worldwide.

Speaking at the start of the mass, the Archbishop of San Giovanni Rotondo, Domenico d'Ambrosio, said this is a feast day because we want to celebrate the immense holiness of God that reverberates and makes itself visible in creatures that know how to receive his mystery.

Padre Pio's bleeding wounds on his hands and feet were never explained. His followers say the saint could also see into the future and had the gift of bi-location - he could be in two places at the same time.

Church officials exhumed Padre Pio's body from a crypt in March. They said that although there was no sign of the stigmata, his body was found to be in surprisingly good condition.

About 1,500 people are expected to file past the glass coffin and pray in front of Padre Pio's body on the first day of viewing. Hundreds of thousands more are expected in the coming months.