Pakistan, May 20 -- Two teenage gunmen opened fire on Monday at the Islamic Center of San Diego, California, killing three men outside the mosque, one of them a security guard, before the two suspects were found dead, apparently from self-inflicted gunshot wounds, police said, as a prominent Muslim advocacy group slammed the attack.

All of the children attending a school that is part of the center - the largest mosque in the region near the Mexico border - were accounted for and safe after the shooting, which erupted Monday afternoon, San Diego Police Chief Scott Wahl was cited as saying in media reports.

Wahl said the FBI was called in to assist the investigation of the incident, which the police chief said authorities were treating as...