(CNN) -- The State Department on Friday issued a travel alert for U.S. citizens about possible terrorist attacks in the Middle East and North Africa by al Qaeda and affiliated organizations.
"Terrorists may elect to use a variety of means and weapons and target both official and private interests," said the alert, which came after officials said U.S. embassies in Egypt and some other Middle Eastern countries would be closed Sunday as a precaution.
Al Qaeda is linked to a terror threat that prompted the embassy closings, U.S. Rep. Ed Royce told CNN's "New Day" on Friday.
"It's my understanding that it is al Qaeda-linked, all right, and the threat emanates in the Middle East and in Central Asia," said Royce, a California Republican who's chairman of the House Foreign Affairs Committee.
On Thursday, a U.S. official not authorized to speak publicly about the matter called the threat "credible and serious."
It was "directed at American targets overseas," but may not be confined to main diplomatic facilities, the official said.
In addition to Egypt, the State Department action includes diplomatic facilities in Saudi Arabia, Libya, Iraq and Kuwait, according to the agency and Twitter postings.
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A senior State Department official said that the agency has told those embassies to close Sunday, normally the beginning of the work week, and that additional days could be added.
The U.S. Embassy in Israel also will be closed as normal on Sunday.
Diplomatic facilities in the region are for the most part closed or operate with minimal staff on Fridays and Saturdays.
Separately, another U.S. official told CNN that the Obama administration is monitoring threats against the embassy in Sanaa, Yemen.
The official did not say whether the embassy would close.
President Barack Obama met with Yemeni President Abdo Rabu Mansour Hadi at the White House on Thursday. Yemen has been cracking down on al Qaeda.
A U.S. official earlier told CNN the embassy closures were because of "more than the usual chatter" about a potential terrorist threat, which was not specific about time and location.
Officials said the time frame comes with the approaching end of Ramadan and the first anniversary of the terror attack on the U.S. diplomatic compound in Benghazi, Libya, that killed four Americans, including Ambassador Christopher Stevens.
State Department spokeswoman Marie Harf said the agency was taking the steps at diplomatic sites out of an abundance of caution.