A suicide bomber attacked an education centre in the Afghan capital on Friday where hundreds of students were preparing for university exams, killing at least 20 people, most of them young women.
The bombing happened in the Dasht-e-Barchi neighbourhood of western Kabul, a predominantly Shiite Muslim area home to the minority Hazara community, the target of some of Afghanistan's most deadly attacks.
The bomber shot dead two security guards before entering the gender-segregated classroom, student Ali Irfani, who escaped the carnage, told AFP.
"Not many boys were hit because they were at the rear end of the classroom. The bomber entered from the front door where girls were sitting," he said.
Akbar, another student witness, also told AFP that young women made up most of the casualties, with up to 600 people in the hall at the time.
No group has yet claimed responsibility for the blast at Kaaj Higher Educational Centre, which coaches students for university admission tests.
However, the jihadist Islamic State group has claimed previous attacks in the area targeting girls, schools and mosques.
A resident who ferried victims to hospitals said he saw body parts scattered across the floor of the hall.
"Many students were hit by shrapnel in their head, neck and eyes," said Asadullah Jahangir.
Kabul police spokesman Khalid Zadran said 20 people were killed and 27 others wounded.
The United Nations Assistance Mission in Afghanistan (UNAMA) told AFP that at least 24 people were killed and 36 others wounded in the attack, adding the numbers were expected to rise.
A shopkeeper from the neighbourhood said there was a loud explosion and then crowds of students rushed out of the centre.
"It was chaos as many students, boys and girls, tried to escape from the building. It was a horrific scene. Everyone was so scared," he told AFP, requesting anonymity.
Italian NGO Emergency, which operates a hospital in Kabul, said it had received 22 patients, including 20 women, two of whom had died.
"The victims are all between 18 and 25 years old, and most of them were in the classroom to take an exam," it said in a statement.
- 'Shamefaced' -
The Taliban's return to power in Afghanistan last year brought an end to a two-decade war and a significant reduction in violence, but security has begun to deteriorate in recent months.
In April, two deadly bomb blasts on the same day at separate education centres in Dasht-e-Barchi killed six people and wounded at least 20 others.
Friday's attack is a "shamefaced reminder of the ineptitude and utter failure of the Taliban, as de facto authorities, to protect the people of Afghanistan", Samira Hamidi of rights group Amnesty International said in a statement.
The United Nations' special rapporteur on Afghanistan, Richard Bennett, condemned the attack.
"Onslaught on education for Hazaras & Shiites must end. Stop attacks on Afghanistan's future, stop international crimes," he said on Twitter.
US Special Representative for Afghanistan Thomas West described the attack as "heartbreaking", tweeting that there is "no justification for attacking innocent students."
Afghanistan's Shiite Hazaras have faced persecution for decades, targeted by the Taliban during their insurgency against the former US-backed government and by IS -- both of which consider Shiites heretics.
Families on Friday rushed to hospitals where ambulances arrived with victims, and lists of those confirmed dead or wounded were posted on the walls.
"We didn't find her here," a distressed woman looking for her sister at one of the hospitals told AFP. "She was 19 years old."
"We are calling her but she's not responding."
Last year, before the Taliban returned to power, at least 85 people -- mainly girl students -- were killed and about 300 wounded when three bombs exploded near their school in the area.
No group claimed responsibility, but a year earlier IS claimed a suicide attack on an educational centre in the same neighbourhood that killed 24, including students.
In May 2020, the group was blamed for a gun attack on a maternity ward of a hospital in Dasht-e-Barchi that killed 25 people, including new mothers.
Education is a flashpoint issue in Afghanistan, with the Taliban blocking many girls from returning to secondary education. Islamic State also stands against the education of women and girls.