Protesters set fire to several houses in eastern India on Monday in an area where recent clashes between Hindus and Christians have left at least 11 people dead, police said. No one was injured in the latest attack in Orissa state, but police feared the arson will increase tension in a region with a history of violence along religious lines. Senior police official Gopal Chandra Nanda would not say whether the burned homes belonged to Hindus or Christians, but said an investigation was under way. The attacks took place in Tikabali, a town in Kandhamal district that has been the center of the unrest. Police have imposed a strict curfew across the district for the past week. The violence began late last month with the killing of a Hindu leader, which police blamed on Maoist rebels but Hindu activists blamed on Christian militants. In apparent retaliation, Hindu hard-liners set fire to a Christian orphanage, killing a Christian woman and seriously injuring a priest. The violence has spread to include mob attacks on churches, shops and homes. Orissa has a history of Hindu-Christian clashes generally fueled by Hindu suspicions about Christian missionary work among the rural poor. On Sunday, four small churches were burned in a village in southern Orissa, an area that had not seen recent Christian-Hindu violence. No one was injured in those attacks, Nanda said.