Taliban insurgents killed at least 141 people, almost all of them children, after storming an army-run school on Tuesday in Pakistan's bloodiest ever terror attack.
Witnesses described how a huge blast shook the Army Public School in the northwestern city of Peshawar and six gunmen in government paramilitary uniforms went from classroom to classroom shooting children, some as young as 12.
Chief military spokesman General Asim Bajwa said 132 students and nine staff were killed in the eight-hour onslaught.
The toll exceeds the 139 killed in blasts targeting former prime minister Benazir Bhutto in Karachi in 2007.
The Tehreek-e-Taliban Pakistan (TTP) claimed responsibility for the assault, calling it revenge for a major military offensive in the region.
A teenage survivor described how he played dead to escape the militants as they rampaged through the school, hunting for people to kill.
Shahrukh Khan, 16, said he and his classmates ducked below their desks when four gunmen burst into their room.
"I saw a pair of big black boots coming towards me, this guy was probably hunting for students hiding beneath the benches," Khan told AFP from the trauma ward of the city's Lady Reading Hospital
Khan decided to play dead after being shot in both legs, stuffing his tie into his mouth to stifle his screams.
"The man with big boots kept on looking for students and pumping bullets into their bodies. I lay as still as I could and closed my eyes, waiting to get shot again," he said.
"My body was shivering. I saw death so close and I will never forget the black boots approaching me -- I felt as though it was death that was approaching me."
The Lady Reading Hospital was thronged with distraught parents weeping uncontrollably as children's bodies arrived, their school uniforms drenched in blood.
Irshadah Bibi, 40, whose 12-year-old son was among the dead, beat her face in grief, throwing herself against an ambulance.
"O God, why did you snatch away my son? What is the sin of my child and all these children?" she wept.
Police officials said the attack ended around 6.30 pm (1330 GMT), some eight hours after it began, with all six militants dead.
Chief army spokesman General Asim Bajwa said on Twitter the operation was "closing up", but that explosive devices planted by the militants were hampering clearance efforts.
Prime Minister Nawaz Sharif described the attack as a "national tragedy unleashed by savages".
"These were my children. This is my loss. This is the nation's loss," he said.
Nobel peace laureate Malala Yousafzai, herself shot by the Taliban in 2012, said she was "heartbroken" by "the senseless and cold-blooded" killing.
US President Barack Obama condemned the attack as "heinous" and said America would stand by Pakistan in its struggle against violent extremism.
The leaders of India and Afghanistan, Pakistan's sometimes fractious neighbours, added their voices to the outrage.
The school on Peshawar's Warsak Road is part of the Army Public Schools and Colleges System, which runs 146 schools nationwide for the children of military personnel and civilians. Its students range in age from around 10 to 18.
The schools educate the children of both officers and non-commissioned soldiers and army wives often teach in them.
Tuesday's attack was seen as shocking even by the standards of Pakistan, which has suffered thousands of deaths in bomb and gun attacks since the TTP rose up in 2007.
TTP spokesman Muhammad Khorasani said Tuesday's assault was carried out to avenge Taliban fighters and their families killed in the army's offensive against militant strongholds in North Waziristan.
"We are doing this because we want them to feel the pain of how terrible it is when your loved ones are killed," he said.
"We are taking this step so that their families should mourn as ours are mourning."
The military has hailed the offensive as a major success in disrupting the TTP's insurgency.
More than 1,600 militants have been killed since the launch of operation Zarb-e-Azb in June, according to data compiled by AFP from regular military statements.
Talat Masood, a retired general and security analyst, said the attack was intended to weaken the military's resolve.
"The militants know they won't be able to strike at the heart of the military, they don't have the capacity. So they are going for soft targets," Masood told AFP.