GUWAHATI, India, Nov 28 (Reuters) - Tribal rebels shot dead eight people and razed two saw mills in India's restive northeastern state of Assam, police said on Wednesday. About a dozen heavily armed militants of the Dima Halam Daogah (DHD), a group fighting for political autonomy for Dimasa tribespeople, attacked the mills in the North Cachar Hill district and shot at workers, killing eight. More than half a dozen were wounded in the attack. A man identifying himself as a DHD leader telephoned Reuters to say the mill owners, who do not belong to the tribe, had been told to leave. "We ordered the timber merchants to shut down their business in our area, but they did not listen to us. So we took action against them," he said, refusing to give his name. The group killed seven policemen in an ambush in the district earlier this month. India's northeast, comprising eight states, has been racked by separatist and tribal insurgencies for the past 60 years, as locals accuse New Delhi of plundering the region's mineral and forest resources, and investing little in return. (Reporting by Biswajyoti Das; Editing by Jonathan Allen)