LOS ANGELES: Officials say two firefighters have been killed when their vehicle rolled off a mountainside as they battled a massive wildfire in northern Los Angeles County.

County Deputy Fire Chief Mike Bryant said at a news conference that the two men were amid intense fire near Mt. Gleason in the Angeles National Forest on Sunday afternoon when the vehicle crashed.

A tearful Bryant said the men's families have been notified. He did not release their identities or give a cause for the crash.

The fire has consumed 66 square miles, destroyed at least 18 structures and was threatening some 12,000 homes.