The office of the nation's top intelligence official on Sunday denied the assertions of a Democratic lawmaker in Congress that U.S. analysts are able to listen in on telephone calls involving Americans without a court warrant.

"The statement that a single analyst can eavesdrop on domestic communications without proper legal authorization is incorrect and was not briefed to Congress," read an unusual Sunday night statement from the Office of the Director of National Intelligence.

The short statement said Section 702 of the Foreign Intelligence Surveilland Act "targets foreigners located overseas for a valid foreign intelligence purpose, and that it cannot be used to target Americans anywhere in the world."

The statement seemed to have been issued to knock down a story published over the weekend by the computer web site CNET, which claimed that thousands of analysts at the National Security Agency "can listen to domestic phone calls."

That came from an exchange made in a hearing last week with the FBI Director by Rep. Jerry Nadler (D-NY), who claimed lawmakers had been told in a secret briefing that no court warrants were needed for NSA eavesdropping.

In a back-and-forth with FBI Director Robert Mueller, Nadler asked what happens when analysts see a phone number that "looks suspcious" in terms of terrorism and a review of phone metadata acquired by U.S. intelligence.

Here is that exchange:

NADLER: (talking about examination of phone metadata) "And you as a result of that, think that this phone number...looks suspicious and we ought to actually get the contents of that phone, do you need a new specific warrant?

MUELLER: "You need at least a National Security Letter; all you have is a telephone number, you do not have subscriber information, so you need the subscriber information, you would have to get a National Security Letter to get that subscriber information. And then if you wanted to do more..."

NADLER: "If you wanted to listen to the phone..."

MUELLER: "Then you have to get a special, a particularized order from the FISA court directed at that particular phone, of that particular individual.

NADLER: "Now, is the answer you just gave me classified?

MUELLER: "Is what?"

NADLER: "Is the answer you just gave me classified in any way?"

MUELLER: "I don't think so."

NADLER: "Okay, then I can say the following - we heard precisely the opposite at the briefing the other day."

I heard that exchange as it happened on Thursday, but didn't report on it, because it seemed to me that there was some kind of mixup on the details by the Congressman, as his assertion ran contrary to the legal guidance for NSA surveillance programs that had been given in public by the NSA Director.

But, because of the CNET story - and especially the headline - it gained a lot of traction over the weekend on the internet, prompting the DNI statement:

"The statement that a single analyst can eavesdrop on domestic communications without proper legal authorization is incorrect and was not briefed to Congress. Members have been briefed on the implementation of Section 702, that it targets foreigners located overseas for a valid foreign intelligence purpose, and that it cannot be used to target Americans anywhere in the world."

Rep. Nadler also issued a statement, saying the NSA has told him no eavesdropping is possible without a warrant - effectively knocking down the story as well.

NSA officials have pledged to publicly release more information about its surveillance efforts - we'll see what we get this week.