The U.S. Embassy (searchin Saudi Arabia (searchsaid Tuesday that it fears renewed attacks on housing complexes for Westerners in the capital and barred diplomats from visiting them at night.

Militants attacked three compounds for foreigners in Riyadh (search) in May, detonating vehicle bombs that killed 35 people including the nine assailants. Another homicide attack killed 17 people in the capital on Nov. 8.

Embassy spokeswoman Carol Kalin told The Associated Press by phone from Riyadh on Tuesday that the Seder Village compound in Riyadh has been under "active surveillance" by terrorists and other housing complexes may also be targeted.

Kalin said the embassy had barred its American employees and dependents from visiting housing compounds in Riyadh between the hours of 6 p.m. and 6 a.m. "except for official business."

"The Embassy continues to be concerned about the current security situation in Saudi Arabia, particularly the housing compounds in the Riyadh areas," Kalin said.

There are some 30,000 Americans living in the kingdom. The U.S. Embassy was scheduled to resume work Wednesday following a weeklong closure for a Muslim feast.

The U.S. warning comes days after the British Embassy in Riyadh renewed its travel warning on Saudi Arabia, advising Britons against all but essential travel to the kingdom.

"If you choose to travel to, or remain in Saudi Arabia," the British statement said, "you should take all necessary steps to protect your safety and should make sure you have confidence in your individual security arrangements."