Volunteers carry student injured in shootout at a school that was attacked by Taliban gunmen at a local hospital in Peshwar, Pakistan. (Associated Press photo)

Nearly 100 children were killed in Pakistan on Tuesday when Taliban gunmen stormed a military-run school in the city of Peshawar, taking hundreds of students and teachers hostage in the bloodiest insurgent attack in the country in years.Troops surrounded the building and an operation was under way to rescue the remaining children, the army said. A Reuters journalist at the scene said he could hear heavy gunfire from inside the school.Pervaiz Khattak, Chief Minister of Khyber Pakhtunkhwa, the province of which Peshawar is the capital, said 84 children had been killed.It was not immediately clear whether some or all of the children were killed by the gunmen or in the ensuing battle with Pakistani security forces trying to gain control of the building.Outside, helicopters hovered overhead and ambulances ferried wounded children to hospital.An unspecified number of children were still being held hostage in the school, a provincial official said, speaking some three hours after the attack began.The Pakistani Taliban, who are fighting to topple the government and set up a strict Islamic state, have vowed to step up attacks in response to a major army operation against the insurgents in the tribal areas.The hardline Islamist movement immediately claimed responsibility."We selected the army's school for the attack because the government is targeting our families and females," said Taliban spokesman Muhammad Umar Khorasani. "We want them to feel the pain."The army said in a statement that many hostages had been evacuated but did not say how many."Rescue operation by troops underway. 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.Prime Minister Nawaz Sharif condemned the attack and said he was on his way to Peshawar."I can't stay back in Islamabad. This is a national tragedy unleashed by savages. These were my kids," he said in a statement.Military officials at the scene said at least six armed men had entered the military-run Army Public School. About 500 students and teachers were believed to be inside.

© Thomson Reuters 2014

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 lay on the floor. We remained on the floor for an hour. There was a lot of gunfire."When the gunfire died down our soldiers came and guided us out."