Cal Fire crews Thursday battled vegetation fires in Sonoma and Lake Counties.

East of Petaluma, CHP officers were shutting down Lakeville Highway near Stage Gulch Road for a 10-acre blaze near Pegasus Ranch, authorities said.

Passersby reported the blaze at 3:33 p.m.

In Lake County, air and ground crews had a 25-acre fire about 40-percent contained east of Kelseyville, Cal Fire officials said.

Dubbed the "Mount Fire" by Cal Fire, the blaze was first reported at 2:24 p.m. off Konocti Road and Oak Hills Lane.