At least 12 people were killed and four others injured in a shooting at a government building in Virginia, United States, on Friday, according to BBC.

Police said the suspect, who is a longtime municipal employee in Virginia Beach, fired indiscriminately on several floors of the building. The gunman, whose identity was not released, was killed during a firing exchange with the police.

Police Chief James Cervera said a police officer was among the six people injured, but his protective vest saved him, according to The Washington Post. Police believe the gunman acted alone but the motive for the shooting is not clear.

Cervera said the shooting happened around 4 pm (1.30 am on Saturday India time) when the employee of the Public Utilities Department entered the building in the city’s Municipal Center, and “immediately began to indiscriminately fire upon all of the victims”, reported AP.

“This is the most devastating day in the history of Virginia Beach,” Mayor Bobby Dyer said. “People involved friends, co-workers, neighbours, colleagues.”

Virginia Beach Vice Mayor James Wood said people can take guns into public buildings, but not schools or courts, according to CNN.