The attackers — aged 17 and 18 — stormed the mosque complex around 11:40am local time, killing a security guard and two other men outside the worship centre before later being found dead inside a vehicle from apparent self-inflicted gunshot wounds.

Five people, including two teenage suspects, were killed on Monday after gunmen opened fire at the Islamic Center of San Diego in California, United States, in what authorities are investigating as a possible hate crime.

The attackers — aged 17 and 18 — stormed the mosque complex around 11:40am local time, killing a security guard and two other men outside the worship centre before later being found dead inside a vehicle from apparent self-inflicted gunshot wounds.

The Islamic Center of San Diego is regarded as the largest mosque in San Diego County.

San Diego Police Chief, Scott Wahl, said the FBI and local law enforcement had opened a hate crime investigation into the attack.