ABU DHABI ø The United States has alerted its 30,000 citizens in Saudi Arabia to the threat of imminent terrorist attacks.

The U.S. embassy in Riyad issued a security warning that Americans remain a target of Al Qaida and related groups. The warning said Islamic insurgents were believed to have targeted housing compounds, hotels, transportation and shopping malls frequented by Westerners.

"American citizens in Saudi Arabia are strongly urged to exercise utmost security precautions and to review the current Travel Warning for Saudi Arabia dated October 27, 2004," the consulate said on Monday.

The warning was issued hours after the U.S. consulate in Jedda was taken over by Al Qaida insurgents, Middle East Newsline reported. No Americans were killed in the three-hour siege.

The U.S. embassy urged Americans to avoid staying in Saudi hotels or housing compounds that are not properly secured. The embassy cited the need for an armed force, inspection of all vehicles and a hardened security perimeter to prevent unauthorized vehicles from approaching the facility.

"Private Americans currently in Saudi Arabia are strongly urged to depart," a State Department travel warning updated as of Tuesday said.

The warning also cited Saudi government facilities as targets of Al Qaida. The embassy has warned that Al Qaida was capable of launching attacks by numerous gunmen in an attempt to penetrate secure facilities.

In April 2004, the United States ordered the departure of non-emergency employees and all dependents of the U.S. embassy in Riyad as well as the consulates in Dhahran and Jedda. Officials said they have not been permitted to return.

On Tuesday, the United States closed all of its diplomatic facilities in Saudi Arabia. U.S. diplomatic sources said some of the facilities would be reopened later this week.

"They want us to leave Saudi Arabia," President George Bush said. "They want us to leave Iraq. They want us to grow timid and weary in the face of their willingness to kill randomly and kill innocent people."