Indian authorities have tightened security in the eastern state of Orissa, after hundreds of Maoist rebels attacked police facilities, killing 15 - including at least 13 police officers.
Police say more than 400 rebels looted a massive quantity of ammunition and weapons in a series of coordinated attacks Friday across the Nayagarh district.
At least 11 police officers were wounded in the attacks, some critically.
Security forces have been combing the area for the rebels, and Orissa state officials have called on India's federal government for help.
In late December, nearly 300 Maoist rebels and their supporters escaped from a prison in eastern India.
The rebels, called Naxalites, say they are fighting for the rights of poor, landless peasants and neglected tribal people. They operate across a wide area of central and eastern India - mostly in the countryside.
The 40-year-old Naxalite insurgency has strengthened and spread to nearly half of the country's 28 states.
Prime Minister Manmohan Singh says the rebels are the gravest threat to India's internal security and are undermining efforts to extend India's economic boom to its poorest regions. He has called for the creation of a special security force to target the rebels.
Some information for this report was provided by AFP, AP and Reuters.