Mother Teresa, revered for her work with the poor in India, is proclaimed a saint by Pope Francis in a ceremony at the Vatican, the BBC reports.

Tens of thousands of pilgrims had flocked to St Peter’s Square for the Mass and canonisation.

Two miraculous cures of the sick after Mother Teresa’s death in 1997 have been attributed to her intercession.

In India, a special Mass was celebrated at the Missionaries of Charity, the order she founded in Kolkata.

Many pilgrims arrived at the Vatican before dawn on Sunday to get a good spot among the masses for the ceremony.

Cardinal Angelo Amato read a brief biography of Mother Teresa’s work, then asked the Pope to canonise her in the name of the Church.

Pope Francis responded: “After due deliberation and frequent prayer for divine assistance, and having sought the counsel of many of our brother bishops, we declare and define Blessed Teresa of Calcutta to be a saint and we enrol her among the saints, decreeing that she is to be venerated as such by the whole Church.”

One pilgrim at the event, Charlotte Samba from Gabon, told Associated Press: “Her heart, she gave it to the world. Mercy, forgiveness, good works. It is the heart of a mother for the poor.”

Some 1,500 homeless people across Italy were brought to Rome in buses to be given seats of honour at the celebration – and then a pizza lunch served by 250 nuns and priests of the Sisters of Charity order.

Large TV screens were set up at Mother House in Kolkata (Calcutta) for the Vatican ceremony.

Senior sister at the Mother House, Mary Lysa, said: “It’s a day of rejoicing, a day of gratitude and a day of many, many blessings.”