As many as 20 people were killed and 40 injured during an attack at the Kabul University on Monday, said sources.
Following the incident, Abdullah Abdullah, head of the High Council for National Reconciliation, said in a tweet, "I strongly condemn today's cowardly terrorist attack on Kabul Uni. Targeting educational institutions is a heinous crime. Students have the right to study in peace and security. I offer my sincere condolences to victims and their families. We will prevail over the forces of darkness."
Tolo News had earlier reported that Afghan and Iranian officials were inaugurating a book exhibition at the university when the explosion and gunfight happened, forcing the students to vacate the area.
No group has claimed responsibility for the attack.
Ahmad Samim, a university student, told journalists he saw militants armed with pistols and Kalashnikov assault rifles firing at the school, the country's oldest with some 17,000 students.
He said the attack happened at the university's eastern side where its law and journalism faculty teach.
The attack came as the insurgents are continuing peace talks with the United States-backed government.
With inputs from agencies
