The head of India's most powerful Hindu group vowed to press ahead with a campaign to convert Muslims and Christians to Hinduism, stoking a sensitive debate that has stalled parliament and threatened Prime Minister Narendra Modi's economic reform agenda.

Mohan Bhagwat of the rightwing Rashtriya Swayamsewak Sangh, which is also the ideological wing of Modi's party, said India is a "Hindu nation" where many Hindus have been forcibly converted to other religions.

"We will bring back those who have lost their way. They did not go on their own," Bhagwat said in a speech late Saturday. "They were lured into leaving."