A grass fire broke out west of Petaluma on Friday afternoon, sending fresh smoke into the region and prompting widespread alarm before it was extinguished.

At least two outbuildings and several commercial vehicles were burned in the early minutes of the fire, reported at 4:20 p.m. off Middle Two Rock Road near Eucalyptus Drive and Lunderberg Avenue, emergency personnel said.

Fire crews from at least six local agencies descended on the area to battle the blaze in high heat and dry conditions.

The fire burned around seven acres before it was contained and knocked down, according to the Wilmar Volunteer Fire Department. Mop up work continued into the night.