© AP Photo/ Hassan Ammar
According to the Al Arabiya broadcaster, a man wearing an explosive belt planned to blow up al-Rasoul al-A'dham mosque, but was killed by Saudi security forces.
The suspect had an accomplice, who was reportedly arrested. Both men were not Saudi citizens, having the status of residents.
Earlier this summer, Saudi Arabia has been hit by a series of terror attacks. On July 4, an assailant set off an explosive device at the Prophet's Mosque parking lot in Medina, targeting security forces reportedly breaking their fast on the second-to-last day of the Islamic holy month of Ramadan.
The deadly blast followed two explosions in Qatif, and came 24 hours after another suicide attack in Jeddah.
Comment: The Saudi regime rules with an iron fist. Any dissent in such a totalitarian state is crushed mercilessly. At the same time, the Saudis have thought they could export the worst of their extremists for use in countries like Libya and Syria. But terrorism is a Frankenstein's monster, and there is 'blowback' even for terrorist states like Saudi Arabia. What happened in this case is anyone's guess.
Update: The Interior Ministry says they questioned a Pakistani man the day before after discovering he was carrying explosives in a sports bag. Police shot him and he died on the way to the hospital.