(CNN) -- Heavy clashes erupted between Iraqi security forces and gunmen who stormed a campus Saturday and used students as human shields, authorities said.
The forces are attempting to re-take the university after the attackers, who are believed to be ISIS members, seized hundreds of students, police officials said.
Professors and other staff also live within the campus, police said.
Explosions rippled through the university while the siege was under way, but police could not provide details on what caused them.
ISIS is the Islamic State in Iraq and Syria, a Sunni Muslim extremist group affiliated with al Qaeda.
The campus is in Ramadi, about 110 kilometers (68 miles) west of Baghdad.
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