A suicide bomber has targeted students preparing for university exams in a predominantly Shi'ite neighborhood in the Afghan capital, Kabul, killing at least 48 people and wounding 67 others, official say.
Most of the victims were young men and women -- high-school graduates -- studying together at a private education center in the Dasht-e Barcha area.
"The wounded have been transferred to nearby hospitals, where they are receiving medical assistance," Health Ministry spokesman Wahid Majroh told RFE/RL's Radio Free Afghanistan on August 15.
"The casualty figures are not yet complete, so it's possible that there will be some changes in the final casualty toll," he added.
Police said the suicide bomber walked into the building while teaching was under way and detonated his bomb belt.
One eyewitness recounted to the Associated Press news agency that he saw parts of human bodies all over student desks and benches in the classroom, the scene of the attack.
Dawlat Hossain, father of 18-year-old student Fareba, said he was on his way to meet his daughter and started running when he heard the explosion.
"There was blood everywhere, all over the room, so scary and horrible," he said.
After finding out that his daughter was safe, Hussain helped move the wounded to hospitals.
Hossain said Fareba, who had left her class just a few minutes before the bombing, was still inside the compound when the blast occurred.
Fareba was traumatized that so many of her friends were killed, but Hossain said she was lucky to be alive.
The Taliban denied involvement in the attack, which came after several weeks of relative calm in Kabul.
There was no immediate claim of responsibility for the blast, but Jawad Ghawari, a member of the city's Shi'ite clerical council, blamed the extremist Islamic State group, which has carried out similar attacks in the past, hitting Shi'ite mosques, schools, and cultural centers.
Ghawari said there were at least 13 attacks on the Shi'ite community in the past two years in Kabul alone.
Afghan President Ashraf Ghani condemned the attack, saying: "By targeting educational and cultural centers, terrorists have clearly shown they are against all those Islamic principles [that strive] for both men and women to learn and study.”
The United Nations Assistance Mission in Afghanistan condemned the attack, saying in a tweet there was "no justification whatsoever for targeting civilians, at any time, under any circumstances."
The head of the UN children's agency, UNICEF, denounced the attack, saying it was "deplorable" that children continue to be hardest hit in the growing violence across Afghanistan.
"Children are not, and must never be the target of violence," UNICEF executive director Henrietta Fore said.