Kabul's security department's spokesman Khalid Zadran told Tolo News the attack took place at Kaaj educational center which also left 27 others hurt.

Khalid Zadran said that students came to the center, in PD13, to take the Kankor university entrance exam, and the number of casualties is preliminary and may increase.

The explosion was heard at around 7.30 am.

An eyewitness and local residents told TOLOnews that today’s event in the Kaaj educational center was a suicide attack. Ambulances are transferring the injured to the nearest hospitals.

No group has so far claimed responsibility for the blast.

Meanwhile, the U.S. Charge d’Affaires Karen Decker condemned the incident and tweeted: "The U.S. strongly condemns today’s attack on the Kaaj Higher Educational Center. Targeting a room full of students taking exams is shameful; all students should be able to pursue an education in peace & without fear."

The UN Assistance Mission in Afghanistan (UNAMA) said: "Amid deteriorating security in #Afghanistan, Kabul hit by another blast today. Many civilian casualties in the callous attack at an education centre in a Hazara & Shia-majority area. The UN family condemns the outrage, extending its deep condolences to all those in mourning."