Police say at least eight Indian paramilitary soldiers have been killed in an attack by Maoist rebels in a forest area in eastern India.

Police officer P.K Sahu said three insurgents also were killed in an exchange of gunfire on Monday in the Dumrinala area, nearly 105 miles (170 kilometers) south of Patna, the capital of Bihar state.

Sahu said early Tuesday that the rebels used improvised explosive devices and fired at paramilitary soldiers in the area that is known to be a rebel stronghold.

The rebels have been called India's biggest internal security threat. They operate in 20 of India's 28 states and have thousands of fighters, according to the Home Ministry.

The insurgents, who say they are inspired by Chinese revolutionary leader Mao Zedong, have been fighting for more than three decades in central and eastern India, staging hit-and-run attacks against authorities as they demand a greater share of wealth from the area's natural resources and more jobs for farmers and the poor.