Riyadh (AFP) - A car bomb exploded Thursday night at a security checkpoint in the Saudi capital Riyadh, killing the driver and wounding two policemen, the interior ministry said.

The blast came with the kingdom on alert for attacks by the Islamic State group of jihadists, who have been blamed for killing policemen and for slaughtering members of the minority Shiite community.

The policemen were in a "stable condition" in hospital, the interior ministry said in a statement carried by the official Saudi Press Agency.

The blast went off when police manning the checkpoint on Al-Hair Road stopped the car for a routine check, said the ministry.

"The driver blew up the car and killed himself," it said.

The ministry identified the driver as 19-year-old Saudi national Abdallah al-Rashid and said the suspect had killed his uncle before blowing himself up.

Asked whether the bombing was linked to the Islamic State jihadist group, General Mansour al-Turki, the interior ministry spokesman, said he was waiting for information from investigators.

He told AFP the explosion happened on a road leading to Al-Hair prison, a high-security facility where Islamic radicals are among those reportedly held.

Thursday's explosion took place on the last day of the holy Muslim fasting month of Ramadan, while fireworks exploded around the Saudi capital before the Eid al-Fitr holiday on Friday.

On successive Fridays in May two suicide bombings at mosques of the minority Shiite community in Eastern Province killed 25 people.

An IS-affiliated group calling itself Najd Province -- which takes its name from the region around Riyadh -- claimed those attacks as well as another suicide bombing that killed 26 people at a Shiite mosque in Kuwait last month.

Five Saudis are among 29 people charged in connection with the Kuwait bombing.

In the southwestern city of Taif on July 3, a policeman was gunned down during a raid in which three people were arrested and flags of the IS group extremists found, police said earlier.

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A fourth suspect was later shot dead.

Saudi Arabia had released a list of 16 men wanted for alleged involvement in the mosque bombings in Eastern Province, home to most of the kingdom's Shiite minority.

The Islamic State group has seized large parts of Iraq and Syria, where it has carried out numerous atrocities and inspired attacks around the world. It considers Shiites to be heretics.