NEW DELHI — Long-simmering land and ethnic disputes erupted in bloodshed in northeastern India when rebels launched coordinated attacks on tribal settlers in Assam state, killing at least 68 people, officials said on Wednesday. The killings took place in five attacks late Tuesday targeting tribal settlers known as Adivasi, who migrated to Assam more than 100 years ago. Most of them worked on tea plantations in the region. Assam's Chief Minister Tarun Gogoi said rebels belonging to a faction of the National Democratic Front of Bodoland were behind the massacre. Bodo rebels have been fighting for a separate homeland for their indigenous tribe, which makes up 10 percent of Assam's 33 million people. They have staged attacks against both Adivasi and Muslim settlers in violence that has left at 10,000 people dead, most of them civilians, in the last three decades. Following the attacks, angry Adivasis surrounded a police station in in Sonitpur, where 26 of the victims died, and attempted to attack the officers inside, said S.N. Singh, a top police official. Police opened fire, killing three Adivasis, he said. He said there were incidents of Bodo homes being attacked, but troops controlled the situation. India's Prime Minister Narendra Modi condemned the latest attacks, and Home Ministry rushed several thousand federal paramilitary troops to the region, junior Home Minister Kiren Rijiju said. Many of those killed were women and children, police said. “We are trying to ensure that ethnic violence does not flare up,” Singh said. Singh said that the rebels may been provoked by heavy losses they suffered recently as police intensified operations against the group. A curfew was imposed with a heavy presence by police and paramilitary forces in the two districts where the killings occurred. Dozens of rebel groups have been fighting the government and sometimes each other for years in seven states in northeast India. They demand greater regional autonomy or independent homelands for the indigenous groups they represent. The rebels accuse the federal government of exploiting the region's rich mineral resources but neglecting the local people. In May, rebels from the same group shot and killed more than 30 Muslim settlers in the region. — AP