Private U.S. citizens should consider leaving as well, the department said. And Americans making plans to go to Saudi Arabia were advised to defer any such travel in light of "the potential for further terrorist activities."
The departure of U.S. officials and family members was not ordered, but was voluntary. Expenses were to be paid by the U.S. government.
Americans who travel to Saudi Arabia or remain there despite the warning were told to register with the U.S. Embassy in Riyadh or the consulates in Jeddah and Dhahran so arrangements can be made to keep them up to date.
"The U.S. government continues to receive indications of terrorist threats aimed at American and Western interests," the department said. This includes the targeting of transportation, the statement said.
"American citizens in Saudi Arabia should remain vigilant, particularly in public places associated with the Western community," the department said.