Updated: 10:15 p.m., Eastern time

A former student shot two dozen people in a lecture hall at Northern Illinois University this afternoon, killing five before shooting himself fatally, according to the Chicago Tribune.

None of the victims have yet been identified, but the university said four, including the shooter, had died at the scene and two others had died at the hospital. One of the wounded was the graduate instructor who was teaching the class.

It is not known what the shooter’s motive may have been. The university’s president, John G. Peters, said the gunman was “a former graduate student in sociology” at Northern Illinois who was “not currently enrolled.”

On its Web site, Kishwaukee Community Hospital, in Dekalb, Ill., reported that it had treated 18 victims. The gunman died of a self-inflicted gunshot wound, the police said.

The Northern Star, the campus’s student newspaper, quoted a witness as describing the gunman as “a skinny white guy with a stocking cap” who was dressed in black. The Tribune reported he was armed with a shotgun, two handguns, and lots of ammunition.

Police officers responded to a call of shots fired on the campus around 3 p.m., according to the Police Department of Dekalb, Ill. The shooting took place in Cole Hall, where a geology class was in progress. Classes have been canceled at least through Friday.

The incident occurred less than a week after a woman shot two classmates to death and then killed herself on the Baton Rouge campus of Louisiana Technical College. The Northern Illinois shootings also happened nearly 10 months to the day after 33 people were shot dead at Virginia Tech, in the biggest mass shooting in modern American history.