The Vatican has condemned the burning to death of a Christian orphanage worker in eastern India by Hindu extremists. The murder of the 21-year-old woman was part of a wave of anti-Christian rioting that has now claimed at least 11 lives in the eastern state of Orissa.

The violence was triggered by the death on Saturday of Swami Lakhmananda Saraswati, a prominent Hindu leader. He and four others were shot by suspected Maoist militants, according to police.

Followers of the Vishwa Hindu Parishad (VHP), the extremist group for which Saraswati was a figurehead, retaliated through attacks on scores of Christian targets, including murders, rapes and the destruction of dozens of churches, locals say.

Saraswati had been at the forefront of a campaign to prevent low-caste Hindus and tribal villagers from converting to Christianity. The riots took place after claims by Hindu hardliners that "Christian militants" were behind his death.

Cardinal Jean-Louis Tauran, a senior Vatican official, called the attacks on Christian targets "a sin against God and humanity". He added: "Certainly religion cannot be invoked for crimes of this type."

In an official statement the Vatican said it "expresses its solidarity with local Churches and the religious orders involved, and condemns these actions, which are an affront to dignity, peoples' freedom, and endanger peaceful civil coexistence."

It also condemned the killing of Saraswati.

The Rome-based Italian missionary agency Misna said that it had received reports that two Jesuit priests had been abducted in the area but had no further details.

The Orissa state authorities tried to calm the violence on Tuesday by imposing a region-wide curfew. After the crackdown was widely violated "shoot-on-sight orders" were issued, according to Satyabrata Sahu, the district administrator.

However, local Christian leaders say that their communities remain in danger.

Dr Joseph D'souza, President of the All India Christian Council, said: "The current number and distribution of security forces in Orissa is nothing like enough to deal with the problem.

"We appeal to the international community to raise their voices to bring peace in an area where more people will die unless something is done urgently."

Orissa has a dark history of inter-religious unrest, often triggered by Hindu suspicion of Christian missionaries.

Saraswati and his followers were widely implicated in the anti-Christian violence that blighted the Kandhamal district of the state over the Christmas of 2007 in which 95 churches were razed and several people killed. The chapter, said to have been triggered by an alleged assault on Saraswati, was branded the worst anti-Christian violence in India since Independence.

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