California firefighters battle several wildfires in Riverside County amid extreme heat

Four wildfires broke out in southern California's Riverside County over the weekend amid sweltering temperatures, with much of the state under excessive heat warnings Sunday.

The largest of the blazes - the Rabbit Fire - had burned 7,600 acres by Sunday and is 10% contained after it ignited Friday afternoon, according to the California Department of Forestry and Fire Protection.

Cal Fire authorities reported a vegetation fire Friday in the community of Lakeview. The Rabbit Fire was first reported as 20 acres and burning with a rapid rate of spread. Cal Fire investigators are still looking into what caused it.

An incident update Sunday said at least 152 structures are threatened by the Rabbit Fire. Authorities said in the update they expect the blaze to be fully contained by Wednesday.

Firefighters made progress on Sunday and downgraded part of the evacuation order in place for the Rabbit Fire to an evacuation warning for several areas, Cal Fire tweeted.

Firefighters were also working to contain the much-smaller Reche, Highland and Gavilan fires that started in Riverside County on Friday and Saturday.

Evacuation orders for the Reche and Highland fires were lifted Sunday, according to an update from Cal Fire and the Riverside County Fire Department.