A longtime city employee opened fire in a municipal building in Virginia Beach on Friday, killing 12 people on three floors and sending terrified co-workers scrambling for cover before police shot and killed him following a “long gun-battle,” authorities said.

Four other people were wounded in the shooting, including a police officer whose bulletproof vest saved his life, said Virginia Beach Police Chief James Cervera. The city’s visibly shaken mayor, Bobby Dyer, called it “the most devastating day in the history of Virginia Beach.”

The shooting happened shortly after 4 p.m. when the veteran employee of the Public Utilities Department entered a building in the city’s Municipal Center, and “immediately began to indiscriminately fire upon all of the victims,” Cervera said. Authorities did not release the suspect’s name, instead choosing to focus on the victims during a news conference.

Police entered the building and got out as many employees as they could, then exchanged fire with the suspect, who was armed with a .45 caliber handgun, the chief said.

Police initially said the gunman shot and killed 11 people, including one who was found inside a vehicle outside the municipal building. Cervera later said one more died on the way to the hospital.

The shooting sent shock waves through Virginia Beach, the state’s largest city and a popular vacation spot in southeastern Virginia. The building where the attack took place is in a suburban complex miles away from the high-rise hotels along the beach and the downtown business area.

Virginia Gov. Ralph Northam said in a statement he was devastated by the “unspeakable, senseless violence,” and is offering the state’s full support to survivors and relatives of the victims.

“That they should be taken in this manner is the worst kind of tragedy,” the governor said during the news conference.

The White House said President Donald Trump had been briefed and was monitoring the situation.

Spoke to Virginia Governor @RalphNortham last night, and the Mayor and Vice Mayor of Virginia Beach this morning, to offer condolences to that great community. The Federal Government is there, and will be, for whatever they may need. God bless the families and all!

— Donald J. Trump (@realDonaldTrump) June 1, 2019

Megan Banton, an administrative assistant who works in the building where the shooting happened, said she heard gunshots, called 911 and barricaded herself and about 20 colleagues inside an office, pushing a desk against a door.

“We tried to do everything we could to keep everybody safe,” she said. “We were all just terrified. It felt like it wasn’t real, like we were in a dream. You are just terrified because all you can hear is the gunshots.”

She texted her mom, telling her that there was an active shooter in the building and she and others were waiting for police.

“Thank God my baby is OK,” Banton’s mother, Dana Showers, said.

At a nearby middle school, friends and relatives were reuniting with loved ones who were in the building when the shooting happened. They included Paul Swain, 50, who said he saw his fiancee from across the parking lot, clearly in an agitated state.

“I think she knew some of the people,” he said.

Outside the school, Cheryl Benn, 65, waited while her husband, David, a traffic engineer with the city who was in the building where the shooting happened, gave a written statement to detectives.

She said her husband initially called her from a barricaded room and said it sounded as if someone had been working with a nail gun. Then he saw the bodies.

“This is unbelievable for Virginia Beach,” Cheryl Benn said. “By and large, it’s a pretty calm and peaceful place to live.”

Picture perfect neighbor’ among the slain in mass shooting

Joshua Hardy was a neighbor who would mow the lawn next door as a favor. One of his grieving neighbors returned that favor Saturday as a posthumous tribute after Hardy became one of the 12 people killed in a mass shooting at a city building in Virginia Beach.

“In the Josh fashion, I dropped my mower down a little extra lower because that’s what he would have done today,” said Clay Rosser, 44. “He cut his grass kinda like clockwork. He was a very meticulous guy.”

Rosser also fashioned a wooden cross and planted it in the front yard of Hardy’s home, where the 52-year-old city engineer lived alone. Neighbors described Hardy as a deeply religious man.

“He was the picture perfect neighbor,” said Damion Houston, 48. “God fearing man. Always trying to keep people’s heads in the right place and give you hope.”

Houston said Hardy’s brother stopped by the house Friday night, looking for him, when he got a call to go over to a school where people were learning the fate of loved ones. Neighbors’ worst fears were confirmed when the names were released Saturday morning.

During a Saturday news conference, city officials identified the 12 killed in the shooting Friday at a Virginia Beach municipal building, showing their photos, and giving details of their lives. Eleven of the twelve were city employees; one was a contractor.

The other victims are:

Laquita C. Brown of Chesapeake: A right of way agent with more than four years in public works.

Tara Welch Gallagher of Virginia Beach: An engineer with six years in public works.

Mary Louise Gayle of Virginia Beach: A right of way agent with 24 years in public works.

Alexander Mikhail Gusev of Virginia Beach: A right of way agent with nine years in public works.

Katherine A. Nixon of Virginia Beach: An engineer with 10 years in public utilities.

Richard H. Nettleton of Norfolk: An engineer with 28 years in public utilities.

Christopher Kelly Rapp of Powhatan: An engineer with 11 months in public works.

Ryan Keith Cox of Virginia Beach: An account clerk with more than 12 years in public utilities.

Michelle “Missy” Langer of Virginia Beach: An administrative assistant with 12 years in public utilities.

Robert “Bobby” Williams of Chesapeake: Special projects coordinator with 41 years in public utilities.

Herbert “Bert” Snelling of Virginia Beach: A contractor there to fill a permit.

(AP)