Car bombs exploded across the Iraqi capitol of Baghdad Saturday night, while militants stormed Anbar university, taking dozens hostage.

Militants killed three police officers who were guarding the school’s gate before storming the campus and holding students hostage in a dorm. The development comes amid violence in Anbar province that has pitted Sunni Muslims against the Shiite-led government. While government-allied forces have fought with militants in the nearby cities of Ramadi and Fallujah, Anbar University has largely been left alone.

Ahmed al-Mehamdi, a student at the university and one of the hostages, said that after waking up to the sound of gunfire, he witnessed militants dressed in black running across the campus. “The gunmen took some students to other university buildings,” al-Mehamdi said in an interview by phone from the building in which he was held, adding “For the rest of us, we are still trapped in our rooms and everybody is in panic, especially the Shiite students.”

After several hours, the militants left the university, under circumstances that still remain unclear. While authorities waited for bomb disposal experts, fearful that explosives had possibly been left behind, students were evacuated by bus. Gunfire erupted as security forces opened fire on fleeing militants.