A car bomb exploded Thursday night at a security checkpoint in the Saudi capital Riyadh, killing the driver and wounding two policemen.

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 attack was blamed by the so-called 'Islamic State of Iraq and the Levant' (ISIL) takfiri group, which has been blamed for killing policemen and for slaughtering several civilians.

ISIL branch in Najd, the central region of Saudi Arabia, said on its Twitter account that Thursday's attack was a message to jihadists held in Riyadh's Al-Hair prison that they had not been forgotten.

"Let the Muslim captives in Al-Hair and everywhere know that we will not relent or tire until we release them from imprisonment, with permission from Allah," SITE quoted the tweet as saying.

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

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 ISIL, General Mansour al-Turki, the interior ministry spokesman, said he was waiting for information from investigators.

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 ISIL group terrorists found, police said earlier.

A fourth suspect was later shot dead.