Reports: Several people shot at Northern Illinois University

• (CNN) -- At least two people were shot and several injured shortly before 4 p.m. CT at Northern Illinois University outside Chicago, CNN affiliates are reporting.

Ambulances line up at Northern Illinois University after a shooting.

The gunman who opened fire in Cole Hall, a lecture building, is dead, according to DeKalb police, the Chicago Sun-Times is reporting.

According to the Chicago Tribune, the DeKalb County coroner's office said no fatalities had been immediately reported.

A local hospital tells CNN affiliate CLTV that it expects to receive 15 patients and has so far treated at least two.

CLTV reports that Kishwaukee Medical Center in DeKalb is treating six people with head wounds.

A woman named Corrine described the scene to CLTV, saying she was "carried out" of Cole Hall by a "wave" of students running for their lives.

"When one of the kids said, 'This guy is shooting!' I just ran to the next building as fast as I could and hid in an empty classroom."

Officers responded to a call of shots fired on campus around 3 p.m., DeKalb County Sheriff Roger Scott told the Tribune.

A professor at the school said there was a person with a gun in Cole Hall, a large lecture hall in Watson Hall. Scott said it was possible the assailant may have taken his own life.

The university had ordered its student body to seek shelter, and it canceled classes Thursday.

"Its has been confirmed that there has been a shooting on campus and several people have been taken away by ambulance," the school said in a posting on its DeKalb campus Web site. "All classes are canceled on the DeKalb campus. People are urged not to come to campus."

A law enforcement official being briefed on the situation tells CNN that the shooter used at least a shotgun. The official declined to be identified further because the incident was still developing.

An spokesman with the Bureau of Alcohol, Tobacco, Firearms and Explosives tells CNN that some of its agents are on the scene -- strictly in an assistance role. He says one of the things ATF agents would do is help trace the weapon or weapons used. An FBI spokesman says several of that agency's agents were also en route to the scene to assist.

DeKalb is 65 miles west of downtown Chicago and 45 minutes southeast of Rockford. E-mail to a friend