As many as 84 children have been killed in a Taliban attack on a school in the Pakistani city of Peshawar, the regional chief minister has said.

Five or six militants wearing military uniforms entered the Army Public School in Peshawar on Tuesday in the Pakistani Taliban’s highest profile attack in months. Gunfire and helicopters were heard outside the school as troops surrounded the building and ambulances carried the wounded to hospital. Details were sketchy in the unfolding situation and it was unclear what was going on inside. Around 500 students and teachers were believed to be present. The army said in a statement that many hostages had been evacuated but did not say how many. “Rescue operation by troops under way. Exchange of fire continues. Bulk of student(s) and staff evacuated. Reports of some children and teachers killed by terrorist,” the army said in a brief English-language statement. The attack began in the morning hours, with the gunmen entering the school and shooting at random, said a police officer, Javed Khan. Army commandos quickly arrived at the scene and exchanged fire with the gunmen, he said. One student inside the school at the time of the attack told a private television channel: “We were in the examination hall when all of sudden firing started and our teachers told us to silently lie on the floor. We remained on the floor for an hour. There was a lot of gunfire.” The Tehreek-e-Taliban Pakistan (TTP) claimed responsibility for the attack. It comes as the Pakistani military wages a major offensive against Taliban and other militants in the tribal area of North Waziristan. The Pakistani Taliban, who are fighting to topple the government and set up a strict Islamic state, have vowed to step up attacks against Pakistani targets in response.