At least three people were killed in an apparent “horrific incident” at a Los Angeles law enforcement training facility, Attorney General Pamela Bondi said.

The victims, employees of the Los Angeles County Sheriff’s Department, appeared to be handling explosives when there was a blast, sources told ABC News. The facility, a Special Enforcement Bureau compound, also houses the bomb squad.

“Our federal agents are at the scene and we are working to learn more,” Bondi wrote on social media.

This is a developing story. Please check back for updates.