At least 3 deputies were killed in an explosion at the Los Angeles County Sheriff's Training Facility

Authorities confirmed that an explosion at a Los Angeles County Sheriff's Department training facility on Friday morning killed at least three deputies.

Los Angeles County firefighters were dispatched at 7:27 a.m. PDT for an explosion by 1000 N. Eastern Avenue in East L.A., which is near the sheriff department's Eugene Biscailuz Regional Training Academy, 5 miles east of L.A. City Hall, officials said.

The blast was "a critical workplace incident" that resulted in "three Department member fatalities," according to a sheriff’s department statement.

Sources said the explosion was not part of a planned training exercise, and it appears the incident occurred while deputies were moving ordnance on the training facility property.

They did say, though, that it's not normal for the arson and explosives detail to deploy live ordnance, so it's not obvious what blew up.

It wasn't clear right away who the fallen deputies were.

There has been no word on what caused the explosion.

In a series of X tweets, Attorney General Pam Bondi said she talked to Bill Essayli, the U.S. Attorney for the Central District of California, and L.A. County Sheriff Robert Luna about the "horrific incident."

"I just spoke to @USAttyEssayli about what appears to be a horrific incident that killed at least three at a law enforcement training facility in Los Angeles," Bondi wrote. "Our federal agents are at the scene and we are working to learn more.  Please pray for the families of the sheriff’s deputies killed."

Department of Homeland Security (DHS) Secretary Kristi Noem confirmed DHS is working with state and federal law enforcement in relation to the incident.