India is in something of a state of shock after learning from official sources that its first Hindu terror cell may have carried out a series of deadly bombings that were initially blamed on militant Muslims. The revelation is forcing the country to consider some difficult questions.

At least 10 people have been arrested in connection with several bomb blasts in the Muslim-dominated town of Malegaon in the western state of Maharashtra in September, which left six people dead. But reports suggest that police believe the cell may also have carried out a number of previous attacks, including last year's notorious bombing of a cross-border train en route to Pakistan, which killed 68 people. Among the alleged members of the cell are a serving army officer and a Hindu monk.

Bomb attacks are not uncommon in India – there has been a flurry in recent months – but police usually blame them on Muslim extremists, often said to have links to militant groups based in either Pakistan or Bangladesh. As a result, the recent cracking of the alleged Hindu cell has forced India to face some difficult issues. A country that prides itself on purported religious and cultural toleration – an ambition that in reality often falls short – has been made to ask itself how this cell could operate for so long. India's military, which prides itself on its professionalism, has been forced to order an embarrassing inquiry.

The near-daily drip of revelations from police has also caused red faces for India's main political opposition, the Hindu nationalist Bharatiya Janata Party (BJP), ahead of state polls and a general election scheduled for early next year. The BJP and its prime ministerial candidate, Lal Krishna Advani, have long accused the Congress Party-led government of being soft on terrorism that involved Muslims. However, the BJP has refused to call for a clampdown on Hindu groups, and last week Mr Advani even criticised the police over the way they questioned one of the alleged cell members, a woman called Sadhvi Pragya Singh Thakur.

The Prime Minister, Manmohan Singh, phoned his rival to ask him not to politicise the issue or the investigation. "There is a strong case so let the police do their job," he told Mr Advani. While some commentators have expressed surprise about the discovery of the alleged cell, others have pointed out that there has been growing concern about the possible threat from Hindu extremists. In the summer, two members of a right-wing Hindu group were killed while putting together a bomb, and two other suspected members of the same group died in similar circumstances in 2006.

Meanwhile, senior right-wing leaders have made no secret of their wish that Hindus should form suicide squads to protect themselves against Muslim extremists. Bal Thackeray, leader of a group called the Shiv Sena, which has been responsible for communal and regional violence in Mumbai, wrote recently in the party's magazine: "The threat of Islamic terror in India is rising. It is time to counter the same with Hindu terror. Hindu suicide squads should be readied to ensure the existence of Hindu society and to protect the nation."

Observers say the fact that the police have arrested the alleged cell members amid considerable political pressure suggests the growing professionalism of its security forces. "It's the first Hindu cell and it's the first time Hindus have been shackled and taken to jail," said Professor Dipankar Gupta, a sociologist at Delhi's Jawarlahal Nehru University. "I'm quite pleased with the way the police have done their jobs."

Belfast Telegraph