THERMAL, Calif. -

Firefighters were monitoring an overnight debris fire in the east valley Wednesday morning.

The fire was reported in Thermal near Avenue 70 and Harrison street late Tuesday night shortly after 11 p.m.

Riverside county firefighters said flames blackened five acres of vegetation and debris.

Firefighters stayed on scene overnight.

No structures were threatened, and no injuries were reported.

The fire's cause was under investigation.