A Hindu nationalist leader has blamed the rape of a nun in her seventies on what he said was the "Christian culture" of sexual exploitation, as more details of the attack at a convent school near Calcutta emerged.

The comment by Surendra Jain, the general secretary of the right-wing Vishva Hindu Parishad (VHP), also known as World Hindu Council, came amid growing security fears for India's Christian and Muslim minorities who have lamented a rise in communal violence.

Jain said the attackers that stormed the convent in the West Bengal town of Ranaghat, desecrating its chapel and raping an elderly nun, were not Hindu nationalists moved by religious hatred, suggesting the culprits had to be looked for amid the Christian community instead.

"It is a Christian culture to exploit nuns. We don't do such things," he was quoted as saying by the Times of India. "The Vatican received 5,000 complaints of sexual exploitation in five years prompting the pope to appeal for legalisation of gay sex."

Jain, whose organisation counts almost seven million members across the country, went on to dismiss the separate mob destruction of a church construction site in the state of Haryana as the natural reaction of residents angered at alleged attempts by the local priest to convert them.

"There are no Christians living in the village or around it," he said. "The church was for the purpose of conversion. Local people had warned against it. But when it went unheeded, they took whatever action they deemed fit."

"Will the Christians allow us to make a Hanuman temple in the Vatican?" he asked.

Rev Dominic Emmanuel, spokesman for the New Delhi Catholic Archdiocese, said he had no words to respond to Jain's remarks. "How do we even respond to this kind of language? How can one stoop so low," he said.

Haryana police said they detained five people over the weekend attack in the city of Hisar.

In Ranaghat detectives were investigating whether the expulsion of a boy from the convent school in the week leading to the raid was connected to it, Reuters reported.

The Convent of Jesus and Mary school said they received anonymous death threats just days after a quarrel between the nuns and the father of a boy who was thrown out for posting lewd remarks about a female schoolmate online.

A group of 10 men stormed the convent on Friday night (13 March) ransacking the chapel and vandalising holy items, before one proceeded to rape one of the nuns living there.

A source in the convent told local media the attackers remained in the premises for about an hour, eating and pillaging before running away with about Rs 700,000 (£7,000, $11,000).

"They tied up two of the sisters in a room and dragged the septuagenarian nun to another room. After committing the crime, they returned and appeared remorseless," a source who preferred not to be named told The Indian Express.

"They then started opening the refrigerators and took out the food items, including chocolates, cakes, pastries and other sweets meant for the students. Those were brought by a sister who recently went abroad".

Christian representatives in India said the recent string of attacks has made them feel "very vulnerable".

"There is a sense of insecurity that the state will not protect us. The incidents are happening all over India," said Rev Sunil Dandge, a pastor from the southern city of Bangalore.

Prime Minister Narendra Modi, the leader of the mainstream Hindu nationalist Bharatiya Janata Party (BJP), condemned the violence. His office tweeted:

PM is deeply concerned about the incidents in Hisar, Haryana and Nadia, West Bengal. — PMO India (@PMOIndia) March 17, 2015

Modi has however been accused by the opposition of not doing enough to tackle religious violence and condemn extremist Hindu movements, whose actions appear to have grown more brazen since he was voted into power last year.

Since December, right-wing groups allied with the BJP have staged a series of mass ceremonies to convert Christians and Muslims to Hinduism amid claims that some of the participants had been threatened or cheated into attending.

Modi is not new to religion-related controversies. In 2002, when he was chief minister of Gujarat State, he was accused of failing to halt religious violence that killed more than 1,000 people, mostly Muslims.

Some 80% of India's 1.2 billion people are Hindus. Muslims make up almost 15% of the population with Christians, Buddhists and other minorities dividing the remaining share.

Meanwhile, hospital officials in Ranaghat said the nun was now in a stable condition and expected to make a good recovery. No arrests have been made over the case yet.