(CNN) A worker at the sprawling Molson Coors complex in Milwaukee opened fire Wednesday afternoon, killing five employees before taking his own life, the company's chief executive officer and police said.

The suspected shooter, a 51-year-old man from Milwaukee, died from a self-inflicted gunshot wound, police Chief Alfonso Morales told reporters.

Gavin Hattersley, Molson Coors president and CEO, said the gunman was a brewery employee.

President Donald Trump called the shooter a "wicked murderer" and offered his "deepest condolences" to the victims and families. "Our hearts break for them and their loved ones," Trump told reporters during a coronavirus briefing at the White House.

More than 1,000 people were working at the campus, comprised of corporate offices and two breweries, when police began receiving reports of a shooting about 2:08 p.m. (local time), Morales said.

About 10 minutes later, employees began receiving texts and emails from the company warning them about an active shooter, according to texts shared with CNN.

None of the victims had been named as of Wednesday night. Hours after the shooting, police said, many employees were still inside the complex as officers continued searching through the complex and "identify who is missing."

Police said there's no active threat at the complex and they have not discussed a possible motive.

The corporate offices will be closed for the rest of the week and the breweries will remain closed for the time being, Hattersley said.

"There are no words to express the deep sadness many of us are feeling right now. I am on my way to Milwaukee now because in the hours and days ahead, the most important thing is that we support and care for each other," the CEO said.

A 'tragic day' for Milwaukee

Scores of police officers, SWAT teams and FBI agents were seen walking around the city's Miller Valley neighborhood, which is named after the iconic 160-year-old brewery.

Speaking to reporters, Mayor Tom Barrett said a regular work day turned into chaos, not only for employees but for the community.

"This is a tragic day for our city, this is a tragic day for our state. Five families, six families actually are grieving and will be grieving because of this horrific act of this individual," Barrett said. "This is a time for us to think about those families. Because there are 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."

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Wisconsin Lt. Gov. Mandela Barnes said Wednesday's incident was the 11th mass shooting in Wisconsin since 2004.

"We are here on the scene of another American tragedy. Another senseless American tragedy. One that shouldn't have to happen and unfortunately it's in our backyard. And I hate to say that it is in our backyard once again," he said.

US Sen. Tammy Baldwin of Wisconsin also lamented the shooting.

"Gun violence has taken too many lives in Milwaukee and the mass shooting today is heartbreaking," Baldwin tweeted. "I want to thank the first responders who ran into harm's way and saved lives. My office is standing by to help the #MKE community in the wake of this tragedy."

'Find a safe place,' texts warned employees

Several emergency text messages were sent to employees warning them of a shooter on the complex, CNN affiliate WITI reported

"Find a safe place, active shooter on campus," said one of the text messages shared with WITI.

Another employee, who was not at work at the time of the shooting, told CNN they began receiving texts and email communications about 2:18 p.m. (local time).

Law enforcement agencies were respond to the Molson Coors complex.

The first text indicated there was an active shooter in or near "South Packaging, building 4 2nd floor stairwell."

Multiple local and federal law enforcement agencies -- including the Bureau of Alcohol, Tobacco, Firearms and Explosives -- rushed to the scene.

Molson Coors became the parent company of MillerCoors in 2016. Last year, Molson Coors announced it was retiring the MillerCoors name as part of a reorganization.