(CNN) -- Five victims of the mass shooting at an Illinois manufacturing business have died, Aurora Chief of Police Kristen Ziman told reporters Friday evening.
The shooter also was killed. He died in a gun battle with officers, the chief said.
Five officers who were wounded by gunfire, Ziman said, and a sixth officer suffered a knee injury.
The shooter was identified by Ziman as Gary Martin, 45, and authorities believe he was an employee at the company where the shooting occurred. Police said there was no obvious motive.
The shooting took place Friday afternoon at Henry Pratt Company, which says it is one of the United States' largest manufacturers of industrial valves.
An employee at the Henry Pratt company, John Probst, told CNN affiliate WLS the shooter was a co-worker and had a pistol.
"He was shooting everybody," Probst said.
Some patients from the shooting were sent to Mercy Medical Center and Rush Copley Medical Center, according to Mercy spokeswoman Olga Solares.
It was unclear how many patients there were and their conditions, she said.
"My heart goes out to the victims and their families who simply went to work today like any other day," police chief Ziman said.
A spokesman for the city, Clayton Muhammad, said the four officers' conditions were stable.
Aerial video from the scene showed scores of police vehicles outside the neighboring companies. The response included at least six ambulances and six firetrucks.
After the incident, police also put up crime scene tape near the Alro Steel Company.
The Bureau of Alcohol, Tobacco, Firearms and Explosives and the FBI are responding to the scene, the agencies tweeted.
Aurora, a city of about 200,000 people, is about 40 miles west of Chicago. It is the second-largest city in Illinois, according to the city's website. Locals refer to Aurora as "City of Lights," a nod to it being one of the first American cities to implement a fully electric street lighting system.
Aurora has a strong music and arts scene, and is even the setting of the popular buddy-film Wayne's World. Although a suburb of Chicago, Aurora has a long tradition of manufacturing.