A suicide attack at a learning centre in the Afghan capital killed 19 people as students prepared for exams on Friday morning, police said.
The blast happened in the Dasht-e-Barchi neighbourhood of western Kabul, a predominantly Shiite Muslim area home to the minority Hazara community, the scene of some of Afghanistan's most deadly attacks.
Videos posted online and photos published by local media showed bloodied victims being carried away from the scene.
"Security teams have reached the site, the nature of the attack and the details of the casualties will be released later," the interior ministry spokesman Abdul Nafy Takor earlier tweeted.
"Attacking civilian targets proves the enemy's inhuman cruelty and lack of moral standards."
The Taliban's return to power in Afghanistan last year brought an end to the two-decade war and a significant reduction in violence, but security has begun to deteriorate in recent months under the hardline Islamists.
Afghanistan's Shiite Hazaras have faced persecution for decades, with the Taliban accused of abuses against the group when they first ruled from 1996 to 2001.
Hazaras are also the frequent target of attacks by the Taliban's enemy the Islamic State group. Both consider them heretics.
Countless attacks have devastated the area, with many targeting children, women and schools.
Last year, before the return of the Taliban, at least 85 people -- mainly girl students -- were killed and about 300 wounded when three bombs exploded near their school in Dasht-e-Barchi.
No group claimed responsibility, but a year earlier IS claimed a suicide attack on an educational centre in the same area that killed 24, including students.
In May 2020, the group was blamed for a bloody gun attack on a maternity ward of a hospital in the neighbourhood that killed 25 people, including new mothers.
And in April this year, two deadly bomb blasts at separate education centres in the area killed six people and wounded at least 20 others.
Education is a flashpoint issue in Afghanistan, with the Taliban blocking many girls from returning to secondary education, while the Islamic State also stand against the education of women and girls.