North San Diego County–Two brush fires that broke out Monday afternoon in Deer Springs forced the closure of all southbound lanes on Interstate 15, according to Cal Fire officials.

The blazes were reported just after 3 p.m. on I-15 near Gopher Canyon Road, in an unincorporated area of North San Diego County.

As a precaution, Cal Fire diverted southbound traffic to Old Highway 395 towards Vista. Eastbound traffic from Vista to the highway was closed to motorists.

Firefighters battled the blaze on the ground, with air tankers and water-dropping helicopters. According to Cal Fire, the blaze had burned 25 acres, and was 5 per cent contained as of Monday night.

Late Monday afternoon, Caltrans opened the left two lanes, however the right two lanes are closed until further notice for fire department and other emergency personnel.

No structures were damaged. The cause of the fire is unknown at this time.