RIYADH (AFP) - Saudi police shot dead a would-be suicide bomber targeting a mosque in the Shi'ite-dominated district of Qatif, the interior ministry said on Wednesday (Aug 24).

It was one of two attacks disrupted in the kingdom's Eastern Province since early August, when a Syrian and a Saudi were arrested on their way to bomb a restaurant, the ministry said.

Tuesday's attempted attack - the latest targeting the Sunni-ruled kingdom's minority Shiites - happened around sunset prayers, the ministry said in a statement.

Security officers "managed to foil a terrorist operation targeting worshippers" at Mustafa Mosque in Qatif, the ministry said.

When suspicious officers questioned the man, he tried to detonate a bomb in a sports bag on his back, leading the police to open fire.

The suspect died on the way to hospital.

Officers found 4kg of explosives in his bag.

"A search revealed a Pakistani ID which is still being confirmed," the ministry said.

The earlier case happened on Aug 5 when police stopped a suspicious vehicle in Dammam, adjacent to Qatif.

Two suspects tried to flee but were detained.

Officers found guns and a suicide belt with more than 7kg of explosives, the ministry said in a separate statement.

"They were trained by Daesh elements abroad to target, in a suicide operation, Al-Saif Restaurant and Cafe in Tarot" neighbouring Qatif, the ministry said, using an Arabic acronym for the Islamic State in Iraq and Syria (ISIS) group.

Initial investigation identified the suspects as Abdullah al-Ghunaimi, 27, of Saudi Arabia, and Hussein Mohammed Ali, 24, of Syria.

"They were to implement the operation at 11pm the same day," the statement said.

"Investigations so far reveal that two other Syrians are involved and have been arrested."

On July 4, a Pakistani resident of the kingdom blew himself up near the United States consulate in the Red Sea city of Jeddah, wounding two policemen.

It was one of three separate attacks throughout the kingdom that day.

One occurred at a Shi'ite mosque in Qatif, leaving the body parts of three people.

Near Islam's second holiest site, the Prophet's Mosque in Medina, four people died in another suicide blast.

No group claimed responsibility, but CIA director John Brennan said the three bombings bore the "hallmark" of the ISIS group of Sunni extremists.

Since late 2014, ISIS has claimed a series of bombings and shootings targeting Shi'ites in the Sunni-majority kingdom, as well as the security forces.

Dozens of victims were killed, largely in Eastern Province, home to most of the country's Shi'ites.

Authorities arrested 19 people, including 12 Pakistani nationals, after the July attacks.

In another incident this month, a Yemeni accused of running over and stabbing a policeman in the southwestern region of Asir had pledged allegiance to IS, the interior ministry said.

ISIS group leader Abu Bakr al-Baghdadi has called for attacks against Saudi Arabia, which belongs to the US-led coalition bombing the militants in Syria and Iraq.

Last week, the son of Al-Qaeda's slain founder Osama bin Laden urged Saudis to "overthrow" the kingdom's rulers in order to "free" themselves from US influence, Site Intelligence Group reported.

Al-Qaeda waged a campaign of shootings and bombings against foreigners and Saudi security personnel between 2003 and 2007.