Maj Gen Mansour al-Turki said in a statement early today that security forces in the heavily Shiites populated town of Qatif spotted a stolen car yesterday evening and found inside it weapons and remain of munition that cause the explosion.
The incident was reported late Thursday by state-linked Saudi media showing a car engulfed in fire and thick plumes of black smoke.
Violence between Shiite militants and security forces there has increased in recent weeks, with several incidents of militants firing rocket-propelled grenades at police. The Islamic State group has previously launched attacks on Shiites in Qatif.