Fast-moving grass fire burns at least 2 homes, threatens dozens of others in Fairfield, Calif.

A fast-moving grass fire has burned at least two homes and is threatening dozens more in a crowded Northern California neighborhood.

A fire department dispatcher in Fairfield, about 40 miles northeast of San Francisco, says two houses on Marigold Drive near Interstate 80 are engulfed in flames.

KGO-TV shows traffic slowing on the freeway as thick black smoke drifts from a burning hillside onto the interstate.

Evacuations have been ordered.

The cause of the blaze is unknown.