MILWAUKEE (AP) — An employee opened fire Wednesday at Milwaukee’s Molson Coors complex, killing five fellow workers before taking his own life, police said.

The gunman was identified as a 51-year-old Milwaukee man who died of a self-inflicted gunshot wound, police said.

“There were five individuals who went to work today, just like everybody goes to work, and they thought they were going to go to work, finish their day and return to their families. They didn’t — and tragically they never will,” Milwaukee Mayor Tom Barrett said.

Authorities offered no immediate motive for the attack and did not release details about the shooter or how the shooting unfolded.

None of the victims was identified. Police said they were still contacting relatives as of early evening. No one was wounded beyond those who were killed.

Officers were working to clear the more than 20 buildings in the complex where more than 1,000 people work. Police Chief Alfonso Morales said authorities believe the shooter operated alone and that the threat was over.

President Donald Trump addressed the shooting before speaking at the White House about steps his administration is taking to combat the coronavirus.

“Our hearts break for them and their loved ones,” the president said. “We send our condolences. We’ll be with them, and it’s a terrible thing, a terrible thing.”

The attack occurred at a sprawling complex that includes a mix of corporate offices and brewing facilities. At least 600 people work at the complex, which is widely known in the Milwaukee area as “Miller Valley,” a reference to the Miller Brewing Co. that is now part of Molson Coors.

Molson Coors CEO Gavin Hattersley called the shooter “an active brewery employee.”

“Unfortunately, I am devastated to share that we lost five other members of our family in this tragic incident,” he said in an email sent to employees. “There are no words to express the deep sadness many of us are feeling right now.”

He said the office would be closed the rest of the week and the brewery shuttered “for the time being” to give people time to cope.

A group of brewery employees gathered at a nearby bar to talk about what had happened.

“We are all a family. We work a lot of hours together, so we’re all very sad,” said Selena Curka, a brewery employee who was about to start her shift when the complex went on lockdown and she was turned away.

“It’s just weird, because nine times out of 10 you’re going to know the shooter,” said another employee Thomas Milner. “It’s a tight-knit family. Within the brewery we all interact with each other.”

Milner was also on his way to work when the shooting happened, and he was turned away too.

James Boyles told the Milwaukee Journal Sentinel that his wife, Lasonya Ragdales, works at Molson Coors in the claims department. She was texting from inside the facility and told her husband that there was an active shooter and she was locked in a room with a bunch of co-workers, the Journal Sentinel reported.