A gunman killed five people and wounded five police officers Friday afternoon after opening fire inside of a warehouse in the Chicago suburb of Aurora, Illinois, police say.

Aurora Police Chief Kristin Zimen said the suspected gunman, 45-year-old Gary Martin, was killed in an exchange of fire with police after shooting several employees of the Henry Pratt Co. and officers who rushed to the company's warehouse.

Zimen said during a brief news conference that officers were "fired upon immediately" upon responding to the 29,000-square-foot warehouse at about 1:30 p.m. Central time. Police believe Martin was an employee at the warehouse.

The company had fired Martin on Friday before the shooting, police said.

Police say the five wounded officers were taken to local hospitals, and two were then transferred to trauma centers. A sixth officer suffered a knee injury. Police did not take questions but scheduled a second news conference Friday night. Police did not specify if any others were injured, or how many.

Gabriel Gonzales, an Iraq War Marine veteran who can see the Henry Pratt warehouse from his front yard, said the number of police vehicles, flashing lights and armored cars Friday afternoon were giving him flashbacks.

"When you are a combat zone, you expect it," said Gonzales. "I've never seen this many police officers anywhere."

He was watching his grandchildren, who were mesmerized by the activity unfolding through the window, and worrying about their brother Anthony, whose school was put under lock down.

"My grandson had a school lock down at 8 years old. I mean, can you believe that?" Gonzalez said. "Back when I was a kid, it was just tornadoes."

At the news conference, Aurora Mayor Richard Irvin said the shooting marked "a sad day in the city."

"For so many years we've seen similar situations throughout our nation," he said. "To experience it firsthand is even more painful."

Illinois Gov. J.B. Pritzker, D, lauded the efforts of law enforcement officers and first responders before lamenting the "epidemic of gun violence that continues to ravage so many communities."

The victims' families, he said, "join a group that should not exist, yet continues to grow."

Tiffany Probst, 38, a legal assistant, said her best friend saw a post on Facebook about the shooting and started texting "that your dad might be inside!"

Her father, John, has worked as a machinist in the building for more than 40 years. He has three grown children and has five grandchildren. She raced down to the warehouse but was blocked by police.

"I knew there was no way to call him because he's old-school and never has a cellphone," she said. But then she heard from friends that her father was giving television interviews and talking with the police.

"He's safe and talking to the news," she said. "He's not much of a talker, but when it comes to this, I can tell by his voice he's real shaken up. We are looking forward to giving him a hug."

Sen. Tammy Duckworth, D-Ill., tweeted Friday that she was following the situation. "This is a scary, sad day for all Illinoisans and Americans," Duckworth wrote. "Thank you to the brave first responders who risked their lives this afternoon and apprehended the shooter."

"My heart breaks for Aurora," Sen. Richard Durbin, D-Ill., tweeted. "I'm tracking updates on the situation with my staff. Thank you to the members of law enforcement who are responding to the emergency."

Nancy Caal, who works at Erwin's Truck Repair near the scene of the shooting, told The Post that she heard the din of sirens as police cars and ambulances rushed to the building behind hers.

She and two others put the shop on lockdown when they saw armed officers heading toward the adjacent Henry Pratt warehouse.

News reports of an active shooter there confirmed their fears shortly after.

"We are kind of nervous," Caal said. "It looks like something big is going on out there."

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The Washington Post's Mark Berman and Julie Tate contributed to this report.