A Saudi militant group has claimed responsibility for Wednesday's suicide car bombing in Riyadh that killed four people and wounded 148 others.
In a statement posted on an Islamic website, the Al Haramain Brigades says the attack targeted special security and anti-terrorism units in the Saudi capital.
The radical group, whose name refers to Islam's two holiest sites: Mecca and Median, has previously claimed responsibility for last year's bombing of a Saudi security officer's car outside his home in Riyadh.
Wednesday's suicide bombing occurred near the entrance to a government building housing Saudi security forces and the headquarters of the city's traffic department. Officials said the remains of the bomber were found in a charred vehicle.
Saudi officials said they believe the attack was the work of terrorists linked to the al-Qaida network.
The bombing occurred days after a U.S. warning of possible terrorist attacks in Saudi Arabia, where authorities have fought a running battle with Islamic extremists for nearly a year.
Saudi police say that in the past week alone they have seized and defused five other car bombs.
Some information for this report provided by AP and AFP.