KARL: That is exactly right. They've closed those embassies and consulates, Martha, because they are strategically significant and would fit that description, but there is no guarantee that this would be an embassy or a consulate. As a U.S. official told us, we do not know whether they mean an embassy, an air base, an aircraft or trains.
Now, we saw last year with the attack on the consulate in Benghazi, the diplomatic outposts are a possible target, but Martha there is no guarantee this time around that the target list is confined to embassies or consulates.
RADDATZ: Very frightening, Jon. And thank you to you.
And while the NSA helped uncover this latest terror threat, there are also new revelations this morning in the controversy over its secret surveillance programs.
Glenn Greenwald, a columnist for "The Guardian" newspaper has been at the center of all this breaking the story with his interview with Edward Snowden. And he joins us now from Brazil. Good morning, Glenn.
You're reporting there are new frustrations, frustration in congress about being thwarted in the attempts to exercise oversight. What does that mean and who is stopping them?
GLENN GREENWALD, THE GUARDIAN: Members of congress, members from both political parties actually came to us and showed us all kinds of letters and e-mails that they've been exchanging in which they're trying to get the most basic information about what NSA is doing and spying on American citizens and what the FISA court has been doing in terms of declaring some of some of this illegal, some of it legal.
Remember, we keep hearing that there's all kinds of robust oversight by congress and we need not worry, and yet these members of congress, one of whom is Morgan Griffith, a Republican from Virginia, the other Alan Grayson, the Democrat from Florida, showed us and we're publishing this morning very detailed letters trying to get this information and they're being blocked from getting it and they've said, and other members have said, that they are forced to learn about what the NSA is doing from what they're reading and are reporting.
RADDATZ: And when you say they're being blocked, how are they being blocked? People are refusing to give it to them in congress?
GREENWALD: Correct. I think the most amazing thing, one of the most amazing things in this whole episode, Martha, there is a 2011 opinion, 86 pages long from the FISA court, that ruled that much of what the NSA is doing which is spying on American citizens is both unconstitutional in violation of the Fourth Amendment and illegal, a violation of the statute.
This opinion remains a complete secret. The FISA court has said they have no objection to having it released, but the Obama administration insists it has to be secret.
Both members of congress and others have been requesting simply to read that court opinion. And the intelligence committee that is led in the House by Mike Rogers and Dutch Ruppersberger, who represents the NSA district, receives all kinds cash from the defense and intelligence agencies, industries, have refused to allow them access. That's extraordinary to have a court opinion ruling that our government violated the constitution and the law, and not only can't we read it, but neither can our representatives in congress.
RADDATZ: Edward Snowden, do you think there's any way he'd ever accept a deal to come back to the United States.