Witnesses said Monday that they saw body parts at the site of the explosion near Qatif's Faraj al-Omran mosque, which is frequented by people in the holy month of Ramadan.
The first explosion in Qatif destroyed a car parked near the mosque, followed by another explosion just before 7 p.m. local time.
Local media said an attacker detonated his bomb when he was attempting to enter the mosque.
Nasima al-Sada, a resident of Qatif, told AFP that "one bomber blew himself up near the mosque," which is usually used by Shias in downtown Qatif. She added that no bystanders were hurt in the blast.
Qatif in Saudi Arabia's Eastern Province is where most of the country's Shia population lives.
Later on, a bomber detonated his explosives near the security headquarters of the Prophet's Mosque in Saudi Arabia's western city of Medina.
Early reports indicate that two security forces have been killed in Medina bomb blast.
There has been no immediate report on possible casualties from the attacks and no group or individual has so far claimed responsibility of today's blasts in Saudi Arabia.
The blasts, which took place as the Muslim holy fasting month of Ramadan is drawing to its end, followed an earlier bombing on Monday in which an explosion hit the surroundings of the United States consulate in the city of Jeddah, in western Saudi Arabia.
The Saudi Interior Ministry said the attacker was killed and two Saudi policemen were injured in the attack which took place near a hospital.
Since late 2014, Saudi Arabia has been witnessing a series of bombings and shootings claimed by the Daesh Takfiri terrorist group and mostly targeting the country’s Shia Muslims in eastern part of the kingdom.
In January 2016, a bomber targeted a mosque in al-Ahsa, killing four people; Press TV reported.
These attacks in Middle East and around the world by the ISIS terrorists are the result of the ideology of Takfiri Wahhabism which dominates Saudi Arabia government’s thinking.
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