An ISIS terrorist blew himself up during Friday prayers at the Imam Ali Shiite mosque in the village of Al-Qadeeh in the oil-rich eastern Qatif region of Saudi Arabia. At least 20 people were killed and 50 injured. Suicide bombings are rare events in the the oil kingdom in recent years. Qatif is home to millions of Shiites who are employed in the kingdom’s main oil center. DEBKAfile adds: Undercover agents of the Islamic State in Iraq and Syria in Saudi Arabia acted to stir the Shiite minority up into sectarian violence against the Saudi crown.