Twelve people were killed in an attack on a university in Kabul, the Afghan capital, a spokesman for the Chief of Kabul Police tells CNN.
Two gunmen who were still on the site were killed Thursday morning in a police operation.
Seven students, three policemen and two security guards were killed in the attack on the American University of Afghanistan in Kabul campus, Basir Mujahid, the spokesman said.
Thirty students were injured in the attack, which no group has yet claimed responsibility for.
Around 750 students were on campus at the time, he added.
The gunmen detonated explosives and fired guns, witnesses said, causing some students and faculty to flee. Others hid inside buildings, a senior State Department official told CNN.
The first blast occurred at 7:50 p.m., when students were gathering and eating together.
Political science student Farim Ahmad was in his final class of the day when he he heard the first blast.
“It was a huge explosion, there was smoke and fire,” he told CNN. “The windows of our class just shattered.”
He and his classmates were trapped in a corridor outside their classroom before a security guard led them to an emergency exit.
Two professors, an American and an Australian, were abducted from the same university earlier this month. Their whereabouts remain unknown.
Following the incident, students and faculty have received instructions and undergone emergency evacuation drills in anticipation of such an attack, Ahmad said.
He said he had received no information from the university as to when classes may resume.
This attack is “an attack on education,” he said.
Despite its name, few Americans study at the school, a senior US State Department official told CNN.
But a number of Americans serve on the faculty and may have been trapped inside buildings.
The school is regarded as a symbol of cooperation between Afghanistan and the United States.
Ahmad Samin said he was teaching a chemistry class Wednesday evening when the assailants struck.
The attackers opened fire and detonated explosives on the campus. Quickly, the lights went out in Samin’s classroom.
“It was very dark, (and) everyone was running. Everyone started screaming,” said Samin, who is a US citizen. “(It) was the scariest moment in my life.
I was just thinking about my son and daughter who are in (the United States).”
Amid black smoke, he took off running with the students and other faculty, and “the smoke entered my mouth” as he fled, he said.