Firefighters are working to extinguish a brush fire that started from a vehicle fire and spread to surrounding vegetation in the 1900 block of Via Ladera Drive in Rainbow, just south of the San Diego-Riverside county line, according to a tweet by North County Fire. There are no reports of structural damage or injuries from the brusher which charred roughly a quarter of an acre in medium-heavy fuels with a slow rate of spread before it was stopped. Multiple explosions were reported along with the blaze, Cal Fire said. Motorists should avoid the area. City News Service contributed to this report. This is a breaking news story and will be updated as more information becomes available.