LOS ANGELES, July 6 (Xinhua) -- California's Governor Jerry Brown declared Friday a state of emergency in San Diego County due to a fast moving fire in the western U.S. state.

The brush fire has destroyed homes, threatened more homes and caused the evacuation of residents, Brown said in a statement.

Additionally, "the fire has forced the closure of roadways and continues to threaten critical infrastructure," he added.

"High temperatures, low humidity, and erratic winds have further increased the spread of this fire," he said.

According to the statement, the Federal Emergency Management Agency has issued a Fire Management Assistant Grant to assist the mitigation and management because the control of the fire and relevant circumstances, by reason of its magnitude, is likely to go beyond the capability of a single local government and requires the combined forces of several regions.

The blaze, dubbed the West Fire, has burned across an area of 400 acres (around 1.6 square km) with only 5 percent contained by the evening, said the Department of Forestry and Fire Protection (Cal Fire).

The forward spread of the blaze has been stopped, tweeted Cal Fire in the evening.

The West Fire has caused a total of 2,000 customers in the Alpine area out of power while another 900 customers are without power due to the fire dubbed the Vandegrift Fire, which has burnt the Camp Pendleton area.

The latter one led to the evacuation of about 750 families, the San Diego Union-Tribune reported.