Senate Panel Presses N.S.A. on Phone Logs

By CHARLIE SAVAGE and DAVID E. SANGER

WASHINGTON — Senators of both parties on Wednesday sharply challenged the National Security Agency’s collection of records of all domestic phone calls, even as the latest leaked N.S.A. document provided new details on the way the agency monitors Web browsing around the world.

At a Senate Judiciary Committee hearing, the chairman, Patrick J. Leahy, Democrat of Vermont, accused Obama administration officials of overstating the success of the domestic call log program. He said he had been shown a classified list of “terrorist events” detected through surveillance, and it did not show that “dozens or even several terrorist plots” had been thwarted by the domestic program.

“If this program is not effective it has to end. So far, I’m not convinced by what I’ve seen,” Mr. Leahy said, citing the “massive privacy implications” of keeping records of every American’s domestic calls.

At the start of the hearing, the Obama administration released previously classified documents outlining the rules for how the domestic phone records may be accessed and used by intelligence analysts. And as senators debated the program, The Guardian published on its Web site a still-classified 32-page presentation, apparently downloaded by Edward J. Snowden, the former N.S.A. contractor, that describes a separate surveillance activity by the agency.

Called the XKeyscore program, it apparently gives N.S.A. analysts access to virtually any Internet browsing activity around the world, data that is being vacuumed up from 150 foreign sites.

Together, the new disclosures provided additional details on the scope of the United States government’s secret surveillance programs, which have been dragged into public view and public debate by leaks from Mr. Snowden, who remains stranded in a Moscow airport.

The hearing came a week after the House voted narrowly to defeat an amendment to shut down the N.S.A.’s domestic phone record tracking program. The 217-to-205 vote was far closer than expected, and it — along with shifting poll numbers — suggested that momentum against the domestic program was building. In recent days even some of the most outspoken supporters of the program have said they are open to adjusting it.

The Obama administration has been trying to build public support for its surveillance programs, which trace back to the Bush administration, by arguing that they are subject to strict safeguards and court oversight and that they have helped thwart as many as 54 terrorist events. That figure, Mr. Leahy emphasized, relies upon conflating another program that allows surveillance targeted at noncitizens abroad, which has apparently been quite valuable, with the domestic one.

Still, Senator Dianne Feinstein, the California Democrat who is chairwoman of the Senate Intelligence Committee, said she supported overhauling the program but keeping it in place because it generates information that might prevent attacks.

John C. Inglis, the deputy director of the N.S.A., said there had been 13 investigations in which the domestic call tracking program made a “contribution.” He cited two discoveries: that several men in San Diego were sending money to a terrorist group in Somalia, and that a suspect who was already under scrutiny in a subway bomb plot was using a different phone.

Robert S. Litt, the top lawyer in the Office of the Director of National Intelligence, testified that the Obama administration was also “open to re-evaluating this program” to create greater public confidence that it protects privacy while “preserving the essence of the program.” Administration officials have emphasized that the program collects only so-called metadata, and not the contents of phone calls.

Still, the top Republican on the committee, Senator Charles E. Grassley of Iowa, asked skeptical questions about the legal basis for the program while criticizing the director of national intelligence, James Clapper, for making inaccurate statements to Congress about it in March. Mr. Clapper has since apologized.

“Nothing can excuse this kind of behavior from a senior administration official of any administration, especially on matters of such grave importance,” Mr. Grassley said.

A series of slides describing XKeyscore, dated 2008, make it clear that the security agency system is collecting a huge amount of data on Internet activity around the globe, from chats on social networks to browsing of Web sites and searches on Google Maps. The volume of data is so vast that most of it is stored for only three days, although metadata — information showing logins and server activity, but not content — is stored for a month. Several of the pages were redacted by The Guardian.

Some of the servers the agency uses are run by foreign intelligence services of friendly nations, including Britain, Australia, Canada and New Zealand, but other servers may be on the soil of countries unaware the agency is mining Internet “pipes” on their soil. Some of the harvesting of data takes place on the coasts of the United States, and along the Mexican border. Most sites are in Europe, the Middle East, and along the borders of India, Pakistan, and China.

The intelligence analysts search for terrorist cells by looking at “anomalous events” — someone searching in German from Pakistani sites, or an Iranian sending an encrypted Microsoft Word file. But one slide says the system can be used to identify anyone “searching the Web for suspicious stuff.”

The presentation says the system enables analysts to identify and pursue leads even if they do not yet know the name, or the e-mail address, of a suspect. “A large amount of time spent on the Web is performing actions that are anonymous,” it explains.

One example of how analysts might use the system is to search for whenever someone has started up a “virtual private network” in a particular country of interest; the networks are pipelines that add greater security to online communications. N.S.A. analysts are able to use the system to extract the activity retrospectively from “raw unselected bulk traffic,” the documents say, and then decrypt it to “discover the users.”

The agency said its surveillance of the Internet was part of its “lawful foreign signals intelligence collection” and not “arbitrary and unconstrained.” The chairman of the House Intelligence Committee, Representative Mike Rogers, and the ranking Democrat, C. A. Dutch Ruppersberger, said, “The program does not target American citizens.”

The XKeyscore presentation claimed the program had generated intelligence that resulted in the capture of more than 300 terrorists. By contrast, the documents released by the government about the domestic phone log program were more abstract.

They included briefing papers to Congress from 2009 and 2011 about the “very large scale” logging of Americans’ calling records — along with a related program that logged Americans’ e-mails, and that was shut down later in 2011 — portraying the programs as providing a vital and important capability.

But Senator Ron Wyden, an Oregon Democrat on the Senate Intelligence Committee who has been a leading critic of the bulk collection programs, said the program had been shut down because officials were unable “to provide evidence to support the claims” of operational value. Mr. Wyden has also questioned the utility of the phone log program.

The new documents also included an April “primary order” by the Foreign Intelligence Surveillance Court that supported orders requiring phone companies to turn over all customer records. It said the government may access the records only when there are “facts giving rise to a reasonable, articulable suspicion” that the number to be searched is associated with terrorism.

However, it said that the results of each inquiry are then placed in a “corporate store” that analysts may search without any such limits. Intelligence officials have separately said that search results include not just a target’s phone records, but also exponentially larger sets of the records of people in as many as three concentric circles around the target.