KABUL, Afghanistan (AP) -- A brazen, hours-long militant attack on the American University of Afghanistan ended early Thursday after at least 13 people were killed and dozens wounded in the assault on the sprawling campus on Kabul's outskirts, a government spokesman said.
The attack underscored how despite efforts by the Afghan authorities to improve security, militants in this country are still able to stage large-scale and complex attacks, including in the capital.
The dead included seven students and one teacher, according to Afghan authorities. Three police officers and two security guards were also killed, the Interior Ministry said.
No group has yet claimed responsibility for the assault but suspicions are pointing to the Taliban. The group's spokesman, Zabihullah Mujahid, would only tell the media that the Taliban are "investigating."
President Ashraf Ghani laid the blame on neighboring Pakistan, accusing it of supporting the Taliban in sanctuaries across the border, and saying the attack had been "organized" in Pakistan. Ghani spoke by telephone with Pakistan's army chief, Raheel Sharif, and demanded "serious action," his office said. Pakistan's Foreign Ministry "strongly condemned" the attack.
Pakistan's military also issued a statement on the conversation between Ghani and Sharif, saying "Pakistani soil would not be allowed to be used for any type of terrorism in Afghanistan."
It said Kabul had provided three cellphone numbers "allegedly used during the university attack." An investigation had traced them to an Afghan company "whose spillover signal affects some areas along the Pak-Afghan border," it said, without further detail.
Ghani's statement also raised the death toll to 13, saying that a teacher, identified on social media as Naqib Khpolwak, a graduate of Stanford Law School and a doctoral candidate at Oxford University, was also among those killed.
"Most of the dead were killed by gunshots near the windows of their classrooms," said Sediq Sediqqi, the spokesman for the Ministry of Interior. The ministry said 36 people were wounded, including nine police officers.
The assault began just before 7 p.m. Wednesday, a time when hundreds of students typically attend evening classes at the prestigious university, with a suicide car bombing at the university's entrance.
The blast breached the security walls and allowed two other militants, armed with grenades and automatic weapons, to enter the campus, Sediqqi said. The siege of the university lasted almost nine hours, before police killed the two assailants around 3:30 a.m., he added.
More than 200 people, mostly students who had been trapped in university buildings, were rescued by special police units.
Ghani's office earlier said he had visited some of the wounded in the hospital and extended condolences to the victims' families. He condemned the assault as an "attack on educational institutions and public places" and said it would "strengthen our goal to eliminate the roots of terrorism."
The university, located on the western edge of Kabul, was established in 2006 to offer liberal arts courses modeled on the U.S. system, and has more than 1,000 students currently enrolled.
The university remained closed on Thursday and it wasn't clear when it would reopen. Faculty leaders could not immediately be reached for comment.
The U.S. Embassy in Kabul called the attack a "cruel and cowardly act" and said it was "ready to assist Afghan authorities with their continuing investigation in bringing those responsible to justice."
The U.N.'s assistance mission in Afghanistan called the attack an "atrocity." Pernille Kardel, UNAMA's acting head, said in a statement she hoped the attack would not discourage Afghan youth from "continued learning and attaining the knowledge and skills critical to Afghanistan's prosperity."
Associated Press photographer Massoud Hossaini was in a classroom with 15 students when he heard an explosion on the southern flank of the campus.
"I went to the window to see what was going on, and I saw a person in normal clothes outside. He shot at me and shattered the glass," Hossaini said, adding that he fell on the glass and cut his hands.
The students then barricaded themselves inside the classroom, pushing chairs and desks against the door, and staying on the floor. Hossaini said at least two grenades were thrown into the classroom, wounding several of his classmates.
Hossaini and about nine students later managed to escape from the campus through an emergency gate.
"As we were running, I saw someone lying on the ground face down. They looked like they had been shot in the back," he said.
Hossaini and the other students took refuge in a residential house near the campus, and were later evacuated by Afghan security forces.
The Pentagon said U.S. military advisers were on the ground with Afghan security forces at the university. Spokesman Adam Stump said the forces had been embedded with the Afghan units.
The attack came two weeks after two university staffers, an American and an Australian, were kidnapped from their car by unknown gunmen driving home from the campus after evening classes on a Sunday night. Their abductors were men dressed in Afghan military uniforms, officials said at the time. The whereabouts of the abductees remains unknown.
The Taliban have been fighting to overthrow the Kabul government for 15 years, and regard foreign civilians as legitimate targets.
Last month, Kabul was shaken by a massive suicide bombing that struck a peaceful rally by Afghanistan's minority ethnic Hazara community, killing more than 80 people and wounding hundreds.
That attack was claimed by the Islamic State group, which emerged last year in Afghanistan as an affiliate of the militant group fighting in Iraq and Syria. It was the IS Afghan branch's first assault in Kabul and the deadliest attack in the Afghan capital since the U.S.-led invasion to oust the Taliban regime in 2001.
Associated Press writers Rahim Faiez and Amir Shah in Kabul, Afghanistan, and Munir Ahmed in Islamabad contributed to this report.
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