Heavily armed Maoists carried out a massive attack on a camp of Indian Reserve Battalion in violence-ridden Belpahari of West Midnapore district late on Monday night.
At least 16 Maoists stormed the camp at Churimara village, firing from automatic weapons, District Superintendent of Police Ajay Nanda said.
Alert policemen retaliated and exchange around 60 rounds with the ultras. However, there was no report of any injury to anyone on both sides, the SP said.
He said a combing operation has been launched in the deep jungles surrounding the area.
The borders of the district with Purulia, Bankura and Jharkhand have been sealed to facilitate the police operation and paramilitary forces have been called to assist the police.
District Magistrate Dushmanta Nariwala said police had put in place precautionary measures after suspected Maoists were found roaming in the violence-prone areas of Goaltore, Lalgarh and Belpahari recently.