A policeman's gun went off accidentally at the high-security state secretariat 'Nabanna' on Saturday without causing harm to anyone, police said.
A police officer said a shot went off from the service rifle of a State Armed Police constable, Sashanka Mondal, who was on duty at the north gate at 12.27 pm on Saturday.
It appeared to be a case of accidental firing, he said.
As senior police officers rushed to the gate on hearing the gunshot, Mondal was whisked away for questioning and his rifle examined, the officer added.
The bullet had hit the bunker and there was no report of any casualty or injury to anyone, the officer said.
The constable claimed the bullet went off from his rifle accidentally as he was preparing for change of shift. "Prima facie, it appeared to be a case of accidental firing," the police officer said.
A suo motu case was lodged at Shibpur police station and senior police officers at Nabanna talked to the constable and were examining the CCTV footage, he said.