It was not the first time a mosque has been targeted in Saudi Arabia. The report said at least 10 security personnel and three workers were killed.
The claim, by the so-called Hijaz Province of the Islamic State, appeared on IS-affiliated Twitter accounts hours after the blast. They were praying when the bomber struck within their ranks, he said.
No group has claimed responsibility for the attack, however Islamic State has said it was behind a number of attacks in Saudi Arabia in recent months.
Interior Ministry spokesman Maj-Gen Mansour Al Turki said preliminary findings from the investigation suggested the suicide bomber had been wearing an explosive belt.
No one has yet claimed responsibility for Thursday’s attack, according to officials, reported the BBC.
Abdulrahman Sabah Saud, the main suspect, renewed his confession at the second hearing that he transported the Saudi suicide bomber to the Kuwait City mosque attacked in June. A week later, a second suicide bombing claimed by the group outside another eastern Shiite mosque left four dead.
The explosion happened at the headquarters of the SWAT team, which is tasked with domestic security, he added.
In the southwestern city of Taif on July 3, a policeman was gunned down during a raid in which three people were arrested and IS flags found.
Also, in November, a gunman opened fire at a mosque in the eastern Saudi village of al-Ahsa, killing eight people. Saudi Arabia has launched numerous airstrikes in Yemen this year in support of that country’s deposed president, targeting Houthi rebels who took over Yemen’s capital.