As many as 10 homes were being evacuated after an RV fire spread to nearby vegetation on the border of Sabre Springs and Poway Saturday afternoon, authorities said. The blaze was reported about 3:35 p.m. off Scripps Poway Parkway near Pomerado Road. An RV became fully engulfed in flames and spread to brush, according to San Diego Fire-Rescue officials. The fire was about a half-acre and threatening nearby homes, officials said. Some homes along Old Stone Road and Oakview Way were being evacuated. It was not immediately known what sparked the fire or if anyone was injured.