The state SPA news agency said the fighter was killed in a shootout on Friday after a car chase through residential neighbourhoods of the town.

"It transpired that he was wanted in security-related matters ... another participant in the incident was identified and arrested," the official said.

Interior Ministry spokesman Mansur al-Turki said a security officer was killed the previous night when his patrol came under fire in the same town, 340km northwest of Riyadh.

Repeated clashes

Saudi security forces have repeatedly clashed with anti-government fighters blamed for a wave of violence in the desert kingdom since May 2003.

On Monday, security forces killed a man and wounded three others in the eastern al-Ahsaa region while they drove their car towards a checkpoint with its lights switched off.

The Interior Ministry later clarified that the men were not "terror-suspects" and the shootout was a mistake.

Some 90 people have been killed and hundreds wounded in the spate of bombings and shootings in Saudi Arabia - much of it directed at Westerners - over the past 16 months.