SANTA ANA, Calif. — A Southern California city councilman has been charged with sexually assaulting seven women when he was a high-ranking county executive in what prosecutors said Tuesday was an abuse of power and public trust.

Carlos Bustamante, 47, a former Orange County Public Works administration manager, is facing 12 felony charges ranging from false imprisonment to sex offenses stemming from his work at the county over eight years until he resigned his post in 2011.

Bustamante, a Santa Ana councilman, called female employees to his office under the pretense of discussing work and kissed and grabbed them, and sometimes masturbated in front of them, prosecutors said.

The women were reluctant to come forward, fearing they would lose their jobs for speaking out against Bustamante, who was considered by some a rising star in Orange County politics.

‘‘This case exemplifies an abuse of power, an abuse of position, abuse of women, and abuse of trust,’’ Orange County District Attorney Tony Rackauckas said.