A police checkpoint near the Muslim holy city of Mecca was under fire Tuesday, no victims reported.
Police became suspicious when they spotted a black four-wheel-drive vehicle without license plates and tried to stop it at a checkpoint south of the city, the official said.
The assailants refused to stop and started shooting.
"Police fired back, but the assailants managed to disappear into the desert," the official said, speaking on condition of anonymity because he is not authorized to give statements to media. "Thank God nobody was injured."
It was unclear how many people were in the car and the official would not speculate on who the persons inside the car might have been.
But the shooting reflected jitteriness across Saudi Arabia, following last week's announcement the kingdom had arrested 208 suspected terrorists in six cells and thwarted several planned attacks in the largest terror sweep here to date.
The kingdom, which is the birthplace of al-Qaida leader Osama bin Laden, has been waging a heavy crackdown on al-Qaida militants since a 2003 wave of attacks on foreigners here.