During a meeting held at the state secretariat with the SPs of Purulia, Bankura, Jhargram and West Midnapore, and around 355 former Maoists, Banerjee said the BJP was attempting to infiltrate outsiders from neighbouring Jharkhand.
West Bengal Home Secretary Atri Bhattacharya, DG Surajit Purakayasta and ADG (Law and Order) Anuj Sharma were also present at the meeting, the official said.
The chief minister directed the police in the four districts to increase surveillance so that the prevailing peace and tranquillity in the area is not disturbed, he added.