The United States says it is closing its embassies and consulates in many Muslim countries on August 4 after receiving an unspecified threat.
On August 1, U.S. State Department spokeswoman Marie Harf cited information indicating a threat to U.S. facilities overseas.
"The Department has been apprised of information that, out of an abundance of caution and care for our employees and others who may be visiting our installations, indicates we should institute these precautionary steps," she said. "The Department, when conditions warrant, takes steps like this to balance our continued operations with security and safety."
Harf declined to give details on the threat, mentioning only "security considerations."
"It is possible we may have additional days of closing as well," she said. "Of course, depending on our analysis, individual U.S. embassies and consulates will announce whether or not they are open and whether they are implementing restrictions or other measures."
August 4 is a Sunday, which is a workday for many U.S. diplomatic missions in Muslim countries. U.S. diplomatic missions in Europe, Latin America, and many other places are usually closed on Sundays.
Last year, the State Department issued an alert to American diplomatic facilities across the Muslim world about potential violence connected to the anniversary of the September 11, 2001 terrorist attacks on the United States.
On that date last year, a number of American facilities were targeted by demonstrators protesting a film made by an American resident that insulted the Prophet Muhammad.
In Libya, a diplomatic post in Benghazi was assaulted by militants who killed the American ambassador, Chris Stevens, and three others.
That attack was not related to the demonstrations.
With reporting by AP and Reuters