WASHINGTON, May 31 (Xinhua) -- At least 11 people were killed and six hospitalized in a mass shooting on Friday at the Virginia Beach Municipal Center in the eastern U.S. state of Virginia, local police said at a press conference.

The shooter, a longtime employee of the public utilities department, was also killed, said Virginia Beach Police Chief Jim Cervera.

Cervera said the shooter fired "indiscriminately" and was confronted shortly by officers after opening fire on multiple floors.

Among the injured was a police officer whose ballistic vest stopped a bullet, the police chief said. The officer is expected to be recovered.

"This is the most devastating day in the history of Virginia Beach," Mayor Bobby Dwyer said. "The people involved are our friends, coworkers, neighbors and colleagues."

The motive of the shooter was unknown. Local media said the gunman was fired on Thursday and disgruntled.

The shooting began shortly after 4 p.m. eastern time (2000 GMT) in Building 2 of the municipal center, next door to the City Hall. The building houses the planning, public utilities, public works departments, among others.