Walnut Creek firefighters controlled the fire that broke out early Thursday morning at Comcast headquarters.
Units responded to flames reported at the communication company's offices at 1267 Arroyo Way near N. Broadway at around 3:45 a.m., the dispatcher said.
The one-alarm fire was declared under control at about 4:10 a.m. Firefighters remained on the scene conducting mop-up operations as of 6:15 a.m. the dispatcher said.
No injuries have been reported as a result of the blaze.
An investigation into the cause is under way.
BCN has contributed to this report