Crews are fighting a structure fire on Willow Pass Road in Concord, according to a 3:32 a.m. Monday tweet from the Contra Costa County Fire Protection District.
The post -- which included photos of what was described as defensive operations -- advised the public to avoid the area.
According to officials, the building was vacant and no injuries have been reported.
Willow Pass Rd from I-680 into Concord is currently closed to traffic. Authorities ask the public to find alternate routes.
More information will be provided when it is made available.