It's a global travel alert, but the U.S. is concentrating much of its attention on the Muslim world. ABC News spoke exclusively with the Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey.
"The intent is to attack western, not just U.S. interests," said Dempsey.
The alert expires at the end of the month, but one of Conde Nasts' highest rated Mideast travel agents says her clients aren't showing much concern.
"Some people don't even take it into account when the U.S. Does this because they've done it many times," said Rita Zawaideh from Caravan-Serai Travel.
That comment reflects the attitudes of most international travelers we spoke to at SFO Friday night.
"I guess it's an everyday thing. We're used to it with terrorists and whatever," said Richard Clemente from Copenhagen, Denmark.
"I'm from London. We're used to travel problems all the time. If you listen to them all then you wouldn't go anywhere," said Barbara Haricharan from London.
But Bob Baer, a former CIA case officer in the Mideast, says the threat in that region appears to be very real.
"I would say if you don't have urgent business in that part of the world you shouldn't go," said Baer.
The closing of 20 embassies and consulates in the Mideast is a sign the U.S. has picked up what it believes to be a credible threat.
"It has to be fairly specific. The sources of the phone calls are probably pretty well known. My only question is will the attack in fact occur in the Middle East," said Baer.
Baer says Al Qaeda has created diversions before and they can do it again, hence the global travel alert.