The U.S. Embassy in Damascus (search) closed Thursday for security reasons, an official said.

Spokesman Brian O'Rourke said he could not say whether there was a specific threat but noted such measures are taken from time to time.

The embassy was closed to the public "to enable it to reassess its security posture," he told The Associated Press.

A statement posted on the embassy's Web site asked visitors "to refrain from coming to the embassy on Nov. 4."

"We will announce in a future message the reopening of the embassy," the statement added.