Security forces are now in control of a university in Pakistan, hours after militants stormed the campus firing on students and teachers. Officials are still tallying the casualties; so far, at least 20 people are reported dead.

The four attackers died in the gun battle that followed the attack, according to local reports. No clear claim of responsibility has been made; an initial claim that attributed the violence to Pakistan's Taliban has been cast into doubt.

NPR's Philip Reeves reports:

"It happened at a campus in northwest Pakistan, a place called Bacha Khan University. Students were in morning class when the militants burst in. Reports say some students escaped by climbing out of windows."Just over a year ago, there was a public outcry after the Taliban stormed an army school in Peshawar and killed more than 130 children."The government responded with a major crackdown on militancy, and also plans for tighter security at schools and universities. It'll now face questions about whether those measures were enough."

Wednesday's attack took place about 20 miles outside Peshawar, in the town of Charsadda.

According to its website, Bacha Khan University was established in the summer of 2012, with the goal of preparing young Pakistanis to participate in a global economy. Its classes range from mathematics and sciences to agriculture and English.

A Bacha Khan University Facebook page says that those killed include a chemistry professor — who reportedly fired back at the gunmen — along with two women, two guards and a policeman.

That professor is Syed Hamid Husain, who is described in an Agence France-Presse report as firing a pistol at the gunmen and telling students to stay inside their building. Students say he was then shot.

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