The decision was taken at a high-level meeting with the special IG, CID, Damayanti Sen at the state secretariat, director general of police, GMP Reddy, told reporters here.
"All police stations in the state have been asked to maintain a strict vigil against any subversive activity or attempt at sabotage," Reddy said.
Asked if they were suspecting involvement of any terrorist outfit in the blast, Reddy said, "We are not ruling out any possibility. Everything is being looked into."
Two suspected militants — Shakil Ahmed and Sovan Mandal — were killed and another, Hasan Saheb, was injured in the explosion which occurred on October 2 at a house in Khagragarh of Bardhaman district.
Meanwhile, with the arrest of another person in connection with the blast, the number of those apprehended in the case has gone up to three.
Hafez Mollah alias Hasan, who was on Sunday detained by the CID from his house at Khar Duttapa in Purbostholi, about 70km from here, was formally arrested on Monday.
Two women were also arrested on Sunday in connection with the blast in which the involvement of terror outfits like LeT and HuJI is being suspected.
West Bengal government has said that a large amount of bomb-making material and 'incriminating' documents were seized from the blast site.
The state shares international borders with Bangladesh, Bhutan and Nepal. It also shares boundaries with the Indian states of Jharkhand, Bihar, Odisha, Sikkim and Assam.