The U.S. issued a global travel warning to U.S. citizens around the world today out of fear that al Qaeda is planning to carry out attacks on American targets.
The warning, which follows Thursday's announcement of the closings of embassies across the Muslim world on Sunday Aug. 4, urges U.S. citizens to be alert to "the continued potential for terrorist attacks, particularly in the Middle East and North Africa, and possibly occurring in or emanating from the Arabian Peninsula."
The statement identifies al Qaeda as a specific threat.
"There is a significant threat stream and we're reacting to it," Joint Chiefs of Staff Chairman Gen. Martin Dempsey told ABC News during the interview for "This Week," describing the threat as "more specific" than previous threats.
Joint Chiefs of Staff Chairman Gen. Martin Dempsey on the Terror Threat
A U.S. official told ABC News the threat is believed to center around Yemen, but there are indications it could be a broader plot that could involve multiple targets.
"Current information suggests that al Qaeda and affiliated organizations continue to plan terrorist attacks both in the region and beyond, and that they may focus efforts to conduct attacks in the period between now and the end of August," the State Department warning said.
The State Department said that "terrorists may elect to use a variety of means and weapons and target both official and private interests," and reminds U.S. citizens of potential targets such as public transportation and tourist sites, and to take precautions.
"Terrorists have targeted and attacked subway and rail systems, as well as aviation and maritime services," according to the statement.
In Yemen, the likely targets are "where there is a U.S. presence" in the capital of Sanaa, a U.S. official said, which would mean the U.S. embassy and the Sheraton Hotel where many U.S. citizens are located.
The official said the State Department, which was shaken following the attack in Benghazi, Libya, that killed the U.S. ambassador in September 2012, decided to broaden the response and close embassies elsewhere as well
The U.S. will continue to work closely with international partners to counter ongoing terrorism threats, agency officials said.
"We continue to work closely with other nations on the threat from international terrorism, including from al Qaeda. Information is routinely shared between the U.S. and our key partners in order to disrupt terrorist plotting, identify and take action against potential operatives, and strengthen our defenses against potential threats."
The State Department also confirmed that 21 embassies and consulates that would normally be open will be closed on Sunday, including offices at some of America's biggest embassies and closest allies in the Muslim world in Egypt, Baghdad, Kuwait, Saudi Arabia and Yemen.