(Updated with identity of the shooter and types of weapons found at the scene.)

Twelve people were killed and five others injured inside the Virginia Beach Municipal Center on Friday afternoon when a long-time city employee fired on them.

The shooter, identified as DeWayne Craddock, 40, worked as a certified professional engineer for the city's Public Utilities Department. He opened fire shortly after 4 p.m. on multiple floors of Building 2 of the Center, which houses the the city’s utilities and public works opereations.

Craddock was shot dead by officers who entered the building. One officer was shot during the exchange, but was saved by his bulletproof vest, Police Chief James Cervera said.

The motive behind the shooting is not immediately known.

Two guns were found at the scene, a rifle and a .45 caliber handgun with extended magazines and a suppressor. Both are believed to have been used by Craddock in the shooting.

"I can tell you that it was a long gun battle between those four officers and that suspect," Cervera said. The building houses over 400 workers.

Several agencies including the FBI have launched investigations into the shooting. Authorities believe there was only one shooter involved.

President Donald Trump had been briefed and was monitoring the situation, Fox News reported.

“This is the most devastating day in the history of Virginia Beach,” Mayor Bobby Dyer told reporters.

crime scene
This is a representational image showing a crime scene tape in Alexandria, Virginia, on June 15, 2017. Getty Images/Mark Wilson