A US national working at a Saudi naval base has been wounded by an unknown gunman, a Saudi defence ministry official has said. The official was quoted by the official Saudi news agency, SPA, as saying the attack took place at the King Abdul-Aziz base in the eastern town of Jubail. Security forces were looking for the gunman who fled after the shooting. He is said to have been dressed in a Saudi navy uniform. The official added that the American - who worked for a defence contracting company - was in a "good" condition and was recovering in a local hospital from minor gunshot injuries. The attack came a day after the US Embassy in the Saudi capital Riyadh warned about imminent attacks against American targets in Saudi Arabia. Earlier this week, the US announced that virtually all its troops, except some training personnel, would be pulled out of Saudi Arabia by a "mutual agreement" with the Saudi Government. Ever since the 1991 Gulf war, the US has had about 5,000 troops stationed in Saudi Arabia - a figure that rose to 10,000 during the recent conflict in Iraq. The BBC's Heba Saleh in Riyadh says that in recent months there has been a string of shooting attacks against employees of western defence contractors in Saudi Arabia. She says the latest, in February, was the fatal shooting of a British national at a traffic light in Riyadh. **PHOTO CAPTION*** Aerial photograph of the Khobar Towers complex near King Abdul Aziz Air Base, Dhahran, Saudi Arabia.