Indian Christians in Maharashtra state have protested against a book by one of the founders of the right-wing Hindu nationalist Rashtriya Swayamsevak Sangh (RSS) claiming Jesus was a Hindu.

First published in 1946 and written by Ganesh Savarkar, Christ Parichay – translated into English as Jesus was a Tamil Hindu – claims Jesus was a Brahmin and that Christianity is just a sect of Hinduism.

It says his real name was Keshao Krishna and that his mother tongue was Tamil. The author also claims he was rescued from the cross by the Essenes and healed with medicinal herbs. He was then taken to Kashmir and spent the rest of his life in the Himalayas, where his tomb can still be found.

The book has been reprinted by a Mumbai-based trust dedicated to propagating the teaching of Savarkar and his brothers, according to Mid-Day news.

The RSS promotes a Hindu nationalist ideology espoused by the ruling BJP party that has been blamed for outbreaks of violence against Christians and for anti-conversion laws passed in several Indian states.

Groups affiliated to it practise "re-conversion" or "ghar wapsi" ceremonies at which Christians and Muslims are "welcomed back" to the Hindu religion. Many of them are from the poorest communities and the campaign is highly controversial, with Christian and Muslim leaders arguing that their members were targeted with financial and social incentives.

According to the beliefs promoted by the RSS, all Indians were originally Hindus and communities practising different religions are ultimately apostate. The re-issue of Savarkar's book is designed to bolster this argument.

It has drawn fierce criticism from Christians, says Mid-Day. Fr Nigel Barrett, spokesperson for the Archdiocese of Bombay, said: "There is an attempt to re-write history and draw us into controversy. Christianity is well grounded and based on the person of Jesus who without a doubt is a real person in history. The RSS is welcome to claim what they will, it doesn't affect us. Our faith in Jesus is based on a personal encounter with Christ."

Dr Abraham Mathai, President of the Indian Christian Voice and former Vice Chairman of the Minorities Commission, said: "The book is a sign of high ignorance of the author. Jesus Christ was born 2000 years ago in Bethlehem and died at Calvary. Yes, Christianity came first to India rather than the West, when St Thomas, one of Jesus's apostles came here to preach. The basis of this book is completely false."

A delegation to the from the Maharashtra United Christian Council to the Chief Minister led by Rev Sanjay Londhe demanded the book be banned. Londhe asked why, if Jesus were a Hindu, some Hindu organisations were against the Church. "They should not burn churches and attack Christians," he told Mid-Day.

The opposition Congress Party questioned the timing of the book's release. "It appears to be deliberate. They want to create confusion among the Indian masses. They must stop it," party spokesperson Sachin Sawant said.