Suspected Hindu hard-liners set an orphanage run by Christian missionaries on fire in eastern India on Monday, killing one nun and seriously injuring a priest, a police officer said.

Another senior police officer, however, later said the woman killed was probably an employee who was giving computer training to the children in the orphanage.

The attack occurred in Khuntapali, a village in Orissa state, during a strike called by the World Hindu Council to protest the killing Saturday of a Hindu religious leader and four others by suspected communist rebels in another district of the state, Ashok Biswal, superintendent of police, told The Associated Press.

Biswal said a group of Hindu hard-liners converged on the orphanage in Khuntapali, nearly 250 miles (400 kilometers) west of the state capital of Bhubaneshwar, and asked nearly 20 residents to leave the complex.

They then set the orphanage on fire with an Indian nun and priest locked inside, he said.

The nun died and the priest was hospitalized with serious burns, Biswal said.

But the director-general of state police said officers were still investigating and were not sure the woman was a nun.

"Police are investigating. ... The woman most probably was not a nun," said Gopal Chandra Nanda, who is the most senior officer in the state.

The conflicting reports could not immediately be reconciled.

In 1999 an Australian missionary, Graham Staines, and his two sons were killed by a Hindu mob that set their car on fire.

The region is marked by religious tensions between Christian missionaries who work with mostly poor tribes in the region and hard-line Hindu groups that claim the Christians are forcing or bribing people to convert.

Churches deny that residents have been pressured or bribed to change their religious beliefs.

Indian law accepts missionaries but bars forced conversions. Nevertheless, any missionary activity generally provokes controversy.

Hindus account for 84 percent of India's more than 1.1 billion population and Christians about 2.4 percent.