Suspected Muslim militants killed four Saudi policemen today at checkpoints along a road north of Riyadh, a Saudi security source said.
The source also told Reuters that police had managed to defuse explosives packed into two cars in northern Riyadh.
Militants fought a gunbattle with police in Riyadh yesterday.
Saudi Arabia is battling a wave of Islamist violence linked to al Qaeda after suicide bombings killed 50 people last year.
