FBI Terrorism Unit Investigating California Explosion

SAN DIEGO --

The FBI Joint Terrorism Task Force is investigating an explosion that damaged the entrance to the federal courthouse in downtown San Diego in the predawn hours Sunday, according to City News Service.

The loud blast at the Edward J. Schwartz Federal Courthouse, 940 Front St., occurred at about 8:48 a.m., said the FBI's April Langwell.

By noon, no claims of responsibility had been received, Langwell said.

The explosion damaged the front door and lobby area of the building, she said. A photograph of the damage showed a tall window with a tear down the left side and a hole punched through the bottom.

Some metal fragments from the explosion were found across the street, according to a freelance cameraman at the scene.

"It was determined that the cause was a small explosive device," Special Agent Darrell Foxworth told reporters. He went on to say the device might have been a pipe bomb, according to broadcast reports.

No one was injured, San Diego police Sgt. Bob Dare said.