Maoists struck for the second time in four days in West Midnapore district when they attacked a camp of the State Armed Police at Niguria on Tuesday night.
A group of about 20-25 rebels started firing at the camp, under Belpahari police station, around 9 pm.
The SAP personnel retaliated, Superintendent of Police R Rajsekharan said.
Earlier reports said the ultras attacked Central Reserve Police Force men, but it was known later that though the camp belonged to the paramilitary force, it was presently housing SAP personnel.
The shootout lasted for over 15 minutes after which the Maoists fled, Rajsekharan said before leaving for Niguria.
Any casualty on the SAP side was yet to be ascertained.
More forces were being sent to Niguria, he said.
The Maoists had blasted the Locket beat office of the police under Lalgarh police station in the district on August 4.
Security forces had demolished a "martyr's column" erected by the Maoists in Kumarbandh village under Lalgarh police station recently.
The police suspected that both the attacks were linked to that.
The Maoists, however, erected a fresh structure at Bansbere village under Belpahari police station, the sources said.