Explosions on Saturday evening shook the neighborhood of Dasht-e-Barchi, home to a large community of Shiites from the Hazara ethnic minority which has been targeted in the past by Islamic State, a Sunni militant group.
A car bomb was detonated in front of the Sayed Al-Shuhada school and two more bombs exploded when students rushed out in panic.
Officials said most of those killed were schoolgirls. Some families were still searching hospitals for their children.
“The first blast was powerful and happened so close to the children that some of them could not be found,” said an Afghan official, requesting anonymity.
An eyewitness told Reuters all but seven or eight of the victims were schoolgirls going home after finishing their studies. On Sunday, civilians and policemen collected books and school bags strewn across a blood-stained road now busy with shoppers ahead of celebrations for Eid al-Fitr next week.
Afghan President Ashraf Ghani on Saturday blamed Taliban insurgents, but a spokesman for the group denied involvement and condemned any attacks on civilians.
Pope Francis called the attack an “inhuman act” in remarks to pilgrims in St. Peter’s Square in Vatican City on Sunday.
United Nations Secretary-General Antonio Guterres also condemned the attack and expressed his deepest sympathies to the victims’ families and to the Afghan government and people.
Families of the victims blamed the government and Western powers for failing to put an end to violence and the ongoing war.
Bodies were still being collected from morgues as the first burials were conducted in the west of the city. Some families were still searching for missing relatives on Sunday, gathering outside hospitals to read names posted on the walls, and checking morgues.
“The entire night we carried bodies of young girls and boys to a graveyard and prayed for everyone wounded in the attack,” said Mohammed Reza Ali, who has been helping families of the victims at a private hospital.
“Why not just kill all of us to put an end to this war?” he said.
Security was intensified across Kabul after the attack, but authorities said they would not be able to provide protection to all schools, mosques and other public places.
But the foreign troop withdrawal has led to a surge in fighting between Afghan security forces and Taliban insurgents.
Critics of the decision say the Islamist militants will make a grab for power and civilians live in fear of being subjected once more to brutal and oppressive Taliban rule.
On Twitter, China’s ambassador to Afghanistan, Wang Yu, said the abrupt US announcement of a complete withdrawal of forces had led to a succession of attacks throughout the country.
“China calls on foreign troops in Afghanistan to take into full account the security of people in the country and the region, pull out in a responsible manner and avoid inflicting more turmoil and suffering on the Afghan people,” he said.
Condemning the killing of civilians, India’s Foreign Ministry said the death of more than 50 young girls made this an attack on the future of Afghanistan.
“The perpetrators clearly seek to destroy the painstaking and hard-won achievements that the Afghans have put in place over the last two decades,” a statement said.