By Adam Shaw | Fox News

A Federal Protective Service (FPS) Officer was killed and another injured Friday in a shooting at a federal building in Oakland, Calif., amid protests and violence in the city over the death of Minneapolis man George Floyd.

"We have witnessed an outright assault on our law enforcement community last night in Oakland, California," Acting Homeland Security Secretary Chad Wolf said at a Saturday news conference. "An assassin cowardly shot two Federal Protective Service contractors as they stood watch over a protest."

According to the FBI's San Francisco branch, the shooting occurred at the Ronald V. Dellums Federal Building when a vehicle approached the building and opened fire at the security officers.

Acting Deputy Homeland Secretary Security Ken Cuccinelli said that there were existing threats to attack police stations and federal buildings.

"That violence not only won't be tolerated, we are also committed to ensuring that it won't succeed anywhere, anywhere," he said. "And let me be clear. When someone targets a police officer or a police station with an intention to do harm and intimidate, that is an act of domestic terrorism."

According to The Associated Press, about 1,000 protesters in Oakland smashed windows, poured gasoline on buildings, threw bricks, sprayed buildings with “Kill Cops” graffiti and were met with tear gas from police. Several officers were injured by projectiles.