AURORA, Illinois (WASHINGTON POST) - An employee who was being terminated from his job at an Illinois warehouse opened fire at his workplace on Friday, killing five people and wounding five police officers, authorities said.

Gary Martin, 45, was called into a meeting that afternoon inside the warehouse in the Chicago suburb of Aurora and was told he was being fired.

Martin then shot the three employees who were at the meeting and two others who were nearby using a handgun he owned illegally, Aurora police chief Kristen Ziman told reporters on Saturday (Feb 16).

Martin had a criminal record, including a felony that kept him from owning a gun legally, Ziman said.

Investigators have said little else that would explain the rampage, including why Martin, who had worked at the warehouse for 15 years, was being fired. It is unclear if Martin knew of his termination beforehand.

"I hate that we have to use the term classic workplace shooting. That pains me to do so. At this time I don't know," Ziman told reporters on Friday. "Again, we can only surmise that with a gentleman who's being terminated that this was something he intended to do."

The five wounded officers were taken to local hospitals, two of whom were transferred to trauma centres. All are expected to survive, police said. One warehouse employee suffered non-life-threatening gunshot wounds.

Martin hid in the warehouse, and police spent the next hour and a half finding him inside the massive facility. When police found Martin, he fired at the officers, who then killed him, Ziman said.

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 armoured cars on 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 mesmerised 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 lockdown at eight 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 Governor J.B. Pritzker 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 she started texting "that your dad might be inside!" Her father, John, has worked as a machinist in the building for over 40 years. He has three grown children and has five grandchildren.

Probst raced down to the factory, but it was blocked by police.

"I knew there was no way to call him because he's old school and never has a cellphone," then she heard from friends father was giving TV 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."

Senator Tammy Duckworth tweeted on 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," Senator Richard Durbin 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."

The shooting occurred just a day after the first anniversary of a mass shooting that killed 17 students and staffers at Marjory Stoneman Douglas High School in Parkland, Florida. The young survivors have since become among the loudest advocates for stronger gun laws, spurring a social media movement with the hashtag #NeverAgain. Their activism has led to the creation of the student-led demonstration, March for our Lives.

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 heavily armed officers heading toward the adjacent Henry Pratt warehouse.

"Nobody told us nothing," she said. "But we closed the gates and locked down the shop."

Aurora shares a name with another suburb that endured a mass shooting almost seven years ago. A gunman, James Holmes, opened fire inside a movie theatre in 2012, killing 12 people and injuring 70 others. The similarity was not lost on Nick Metz, the police chief of Aurora, Colorado.

"Months from now as people talk about the mass shooting in Aurora, someone will ask, 'Which Aurora mass shooting are we talking about?'" he said on Twitter.