Gunmen in the Afghan capital stormed the country's largest university, killing 19 people in an hours-long attack on Monday.
The assault coincided with a book fair that attracted senior Afghan and Iranian officials to the sprawling campus, including Iranian Ambassador Bahador Aminian.
Interior ministry officials initially told NPR that the officials were thought to be the target of the attack. It was not immediately clear whether any of the officials were killed or wounded.
Video was posted to social media of what appeared to be students scaling the university's walls to flee the campus amid the crackling of gunfire. Graphic photographs of the carnage were also uploaded by Afghan reporters.
"Unfortunately, there are casualties," Interior Ministry spokesman Tariq Arian said, without elaborating, The Associated Press reports.
One student who escaped, Fathullah Moradi, told Reuters that the assailants "were shooting at every student they saw."
Another student, Ahmad Samim, told journalists that he saw militants armed with pistols and Kalashnikov assault rifles, according to the AP.
The Taliban, whose officials are in peace talks with the U.S.-backed government, has denied responsibility. No other group immediately claimed the attack.
The incident marks the second such attack on an institution of learning in Kabul in less than 10 days, after a suicide bomber late last month blew himself up outside an education center, killing more than 20 people, including many students. The Islamic State claimed responsibility for that attack.
There is a grim history of attacks on centers of learning in Kabul in recent years. Last year, a bomb at Kabul University killed eight people. In 2018, a suicide bomb attack claimed by ISIS killed dozens of teenagers who were studying for university entrance exams at an educational center in a Shiite neighborhood in Kabul. And in 2016, an attack on American University of Afghanistan in Kabul killed 13 people.