By Subir Bhaumik BBC correspondent in Calcutta

A miracle attributed to Mother Teresa has been challenged in the Indian state of West Bengal.

A rationalist group in the state says a woman reportedly cured of cancer by placing a photograph of the nun on her stomach had subsequently received treatment in government hospitals.

Mother Teresa: Revered by many

Doctors who treated the woman, Monica Besra, say she was in pain several years after Mother Teresa died.

Vatican officials earlier this week approved the miracle, and said this would strengthen her case for sainthood.

For several years Prabir Ghosh, general secretary of the Indian Rationalist and Scientific Thinking Association, has challenged Hindu "godmen" and exposed their miracles as what he describes as cheap hypnotic tricks better performed by magicians.

Now he is challenging the claim of the Missionaries of Charity, who say a photograph of their founder, Mother Teresa, when placed over the stomach of 30-year-old Monica Besra, cured her of a tumour.

Undue publicity

Mr Ghosh described the claim as bogus and typical of the process of cult building in all religious orders.

He says Mother Teresa could be considered for sainthood for her services to the poor, adding that it was an insult to her legacy to bestow her sainthood on false claims of miracles.

Mr Ghosh says several doctors have reported to the West Bengal government that Ms Besra continued to receive treatment long after Mother Teresa died.

He said Ms Besra was admitted to hospital with chronic headaches and severe abdominal pain at least a year after Mother Teresa's death.

The doctors say that if the story of the miracle gets what they describe as undue publicity, illiterate and poor villagers may stop taking medical treatment for their maladies and seek miracle cures.

Mr Ghosh says his association, which seeks to promote rational and scientific thinking in India, would expect the West Bengal Government to take legal action against the Missionaries of Charity.

When contacted, the Missionaries of Charity did not react to the charge.