The attack follows an incident in neighbouring Chhattisgarh state on Saturday, where four Maoists were killed and several injured in a gun battle with police.


More than 6,000 people - mostly police, government soldiers, landlords and civilians suspected to be spies - have been killed in violence.


The Naxalites are active in six of India's 28 states - Andhra Pradesh, Jharkhand, Bihar, Karnataka, Orissa and Chattisgarh.