Yemen is home to al-Qaida's most dangerous affiliate, blamed for several notable terrorist plots on the United States. They include the foiled Christmas Day 2009 effort to bomb an airliner over Detroit and the explosives-laden parcels intercepted the following year aboard cargo flights.
Rep. Peter King, who leads the House Homeland Security subcommittee on counterterrorism and intelligence, said the threat included dates but not locations of possible attacks.
"The threat was specific as to how enormous it was going to be and also that certain dates were given," King, R-N.Y., said on ABC.
Rep. Adam Schiff, a House Intelligence Committee member, said the "breadth" of the closures suggests U.S. authorities are concerned about a potential repeat of last year's riots and attacks at multiple embassies, including the deadly assault in Benghazi, Libya, where the U.S. ambassador and three other Americans were killed.
In addition, Interpol, the French-based international policy agency, has issued a global security alert in connection with suspected al-Qaida involvement in several recent prison escapes including those in Iraq, Libya and Pakistan.
Those prison breaks add to the concerns about an attack, said Schiff, D-Calif., also noting the approaching end of the Islamic holy month of Ramadan.
"So you have a lot things coming together. ... But all of that would not be enough without having some particularly specific information," he said.
The Obama administration's decision to close the embassies and the lawmakers' general discussion about the threats come at a sensitive time as the government tries to defend recently disclosed surveillance programs that have stirred deep privacy concerns and raised the potential of the first serious retrenchment in terrorism-fighting efforts since Sept. 11.
The Senate Judiciary Committee chairman has scoffed at the assertion by the head of the National Security Agency that government methods used to collect telephone and email data have helped foil 54 terror plots.