Tehrik-e-Taliban Pakistan (TTP) militants have killed 141 people, including 132 children, at an army-run high school in Peshawar, north-west Pakistan.
Nine teachers and staff members were also killed, with many others wounded in what has been called one of the worst terrorist attacks in the country in recent years.
According to media reports, six Taliban suicide bombers disguised as security guards entered the school on 16 December from the back entrance and went from classroom to classroom, shooting students.
The majority were the children of Pakistani military personnel and were often taught by army wives.
One suicide bomber reportedly detonated a bomb in a classroom of 60 pupils, while five gunmen were killed by the Pakistani commandos in a clearance operation that lasted for nearly eight hours.
The Pakistani military has claimed that approximately 960 students and staff survived.
The terrorist group said the attack was carried out in response to military operations against insurgents in North Waziristan and the Khyber region.
TTP spokesperson Muhammad Umar Khorasani said: "We selected the army's school for the attack because the government is targeting our families and females.
"We are doing this because we want them to feel the pain of how terrible it is when your loved ones are killed."
US President Barack Obama was quoted as saying that the terrorists had 'once again shown their depravity'. Condemning the attack, UN Secretary General Ban Ki-moon called it 'an act of horror and rank cowardice'.
Widely condemned by the international community, the attack prompted the army to intensify air strikes against the terrorists in the Khyber region.
Code-named Zarb-e-Azb, the Pakistani military offensive has been underway since June and has killed an estimated 1,000 militants, with tens of thousands of people displaced, Agence-France Presse reported.
Image: Pakistan Chief of Army Staff general Raheel Sharif talking to an injured student at the Combine Military Hospital in Peshawar, Pakistan. Photo: courtesy of ISPR.