The attack coincides with the 24-hour blockade programme declared by the Maoists in the districts of Birbhum, Bankura, West Midnapore and Purulia.

According to a senior CID official, a big contingent of Maoist cadres, fully armed, descended on Bhimgarh village in Khairasol police station area, which is located at the bordering area of Jharkhand and West Bengal, in the wee hours and planted the explosives to blow up the security set up and the tower.

“We are not yet sure what kind of explosives have been used. A police team has gone over to Khairasol,” said senior officials.

“We have sent a bomb squad to the spot. According to the inputs received from the intelligence, there is a high possibility that the mobile service provider might have refused to give extortion money to the Maoists,” said a senior official.

However, no one was injured as the building located in the security zone was empty when the Maoists triggered the blast.

Shyamal Das, security guard of the office, said: “Around seven armed miscreants walked into our security zone and asked us to leave the place. Two night guards were deployed in the office premises. Both of us were forced to leave at gun point and we were sent to the staff quarters located near the security zone. After a few minutes, we heard a sound of explosion and the entire area was filled with smoke. When we came out of the quarters we found the office had collapsed and a portion of the tower had been damaged.”

A senior district police official, meanwhile, said: “According to the information we have, a squad from Jharkhand sneaked into the area and after triggering the blast, they returned through the same route. We have started maintaining a strict vigil on the state border.”

The Maoists have also gunned down a local CPM leader at Gidighati in Belpahari police station in West Midnapore.