There has been outrage in India over a Hindu leader's comment that Mother Teresa's charity work had one objective - to convert the poor to Christianity.

Mohan Bhagwat is the powerful head of Hindu nationalist organisation RSS, which is close to Prime Minister Narendra Modi's BJP government.

Opposition politicians criticised the remark and many Indians took to social media to express their outrage.

The comments come days after PM Modi vowed to protect religious freedom.

The prime minister's comments followed a string of attacks on churches in Delhi.

Mother Teresa, who worked for nearly 50 years to help the poorest of the poor in Kolkata (Calcutta), founded the Missionaries of Charity and was awarded the Nobel Peace Prize for her work in 1979.

India too recognised her contribution by awarding her Bharat Ratna (Jewel of India), the country's highest civilian honour.

Motivation questioned

"Mother Teresa's service would have been good. But it used to have one objective, to convert the person, who was being served, into a Christian," Bhagwat said while speaking at a function in Rajasthan on Monday

"The question is not about conversion but if it is done in the name of service, then that service gets devalued," he added.

The comment sparked a howl of protest from Christian leaders, opposition politicians and ordinary Indians.

Delhi Catholic Archdiocese Father Savarimuthu said it was "a sad statement".

"Mother Teresa had dedicated her life to the destitute," CNN-IBN quoted him as saying.

The main opposition Congress party demanded an apology from the ruling BJP and said they would raise this issue in parliament.

"Mother Teresa shouldn't be insulted like this," Congress leader Rajiv Shukla said.

MP Derek O'Brien of the Trinamul Congress party said the statement was "condemnable".