Pope John Paul II on Sunday formally declared Mother Teresa 'blessed', bringing to an end one of the fastest beatifications in the Roman Catholic church at a glittering ceremony in Vatican City attended by nearly 250,000 admirers and friends of the diminutive nun from Kolkata, which she made her home.

"Brothers and sisters, even in our days, God inspires new models of sainthood. Some impose themselves for their radicalness, like that offered by Mother Teresa of Calcutta, who today we add to the ranks of the blessed," the Pope said, formally beatifying the Nobel laureate nun who died in 1997.

• Mother's Beatification: Complete Coverage

The ceremony, the penultimate step towards sainthood, makes Mother Teresa the 1,315th beatified person in the Roman Catholic church, enabling her 'limited worship', namely her formal adoration in the Missionaries of Charity chapels and churches.

"In total gift of herself to God and neighbour, Mother Teresa found her greatest fulfillment and lived the noblest qualities of her feminity," the pontiff said.

Appearing frail but in reasonably good form, the Pope, draped in a white vestment embroidered in gold, concelebrated a solemn mass with nine cardinals and Archbishop Lucas Sircar of Kolkata after pronouncing Mother beatified.

Monica Besra, the tribal woman from South Dinajpur district of West Bengal whose claim of a miraculous cure from abdominal tumour at Mother's intercession clinched the honour of beatification for the nun, was flown to the Vatican from Kolkata by the Missionaries of Charity for the ceremony.

Sister Nirmala, who succeeded Mother Teresa as superior-general of the Missionaries of Charity was also present along with Union Minister of State for Law and Justice P C Thomas who represented the Government of India.

In his homily read out by Archbishop Lucas, the Pope described Teresa as "mother to the poor" whose "life is a testimony to the dignity and the privilege of humble service. She had chosen to be not just the least, but to be the servant of the least."

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Stating that Mother's greatness lay in her ability to give without counting the cost - "to give till it hurts" - the Pope said, "As a mother to the poor, she bent down to those suffering various forms of poverty.

"Satiating Jesus's thirst for love and for souls had become the sole aim of Mother Teresa's existence and the inner force that drew her out of herself and made her run in haste across the globe, to labour for the salvation and the sanctification of the poorest of the poor."

With the beatification over, Mother Teresa will require to be formally attributed with another miracle, which should happen after today, to be elevated to sainthood.

In Delhi, the pre-independence era Willingdon Crescent Road in the heart of the national capital was rechristened as Mother Teresa Road as a tribute to the nun. "We had to find a street in keeping with Mother Teresa's stature. So we chose Willingdon Crescent," NDMC chairman V Narayanaswamy said.

Meanwhile, the speed with which beatification was rushed through has raised eyebrows among a section of the Roman Catholic clergy in Vatican City who held that in his hurry to elevate her to sainthood, the Pope had not done justice to the Albanian-born nun's spirit of humility and simplicity.

While most of the clergymen chose not to speak out openly on the matter, priest and cannon law expert Fr A C Jose said, "Mother should have been spared of being made an exception. Humility and simplicity were her outstanding virtues and those should have been respected by putting her at par with other candidates for beatification."

Referring to claims by rationalists and government doctors who treated Monica Besra at Balurghat Sadar Hospital that her tumour was cured medically and in normal course, Fr Jose said, "The whole Diocesan inquiry about Monica's miracle claim is shrouded in mystery. The problem is that the key persons associated with the inquiry had not come out to place facts in the open."

Kolkata, where Mother Teresa worked among the poor for over half a century, commemorated her beatification in Rome through day-long programmes, including prayers and thanksgiving by the Missionaries of Charity, processions by street children and an evening audio-visual concert.

The low-key celebrations began with an hour-long morning prayer at 6 at Mother House, the global headquarters of the Missionaries of Charity, the order founded by the frail Albanian nun. Fr Joseph Maliyakcl conducted the prayer, which was attended by about 200 people.