By James Risen and Eric Lichtblau

Jun. 16- The National Security Agency is facing renewed scrutiny over
the extent of its domestic surveillance program, with critics in
Congress saying its recent intercepts of the private telephone calls and
e-mail messages of Americans are broader than previously acknowledged,
current and former officials said.

The agency's monitoring of domestic e-mail messages, in particular, has
posed longstanding legal and logistical difficulties, the officials
said.

Since April, when it was disclosed that the intercepts of some private
communications of Americans went beyond legal limits in late 2008 and
early 2009, several Congressional committees have been investigating.
Those inquiries have led to concerns in Congress about the agency's
ability to collect and read domestic e-mail messages of Americans on a
widespread basis, officials said. Supporting that conclusion is the
account of a former N.S.A. analyst who, in a series of interviews,
described being trained in 2005 for a program in which the agency
routinely examined large volumes of Americans' e-mail messages without
court warrants. Two intelligence officials confirmed that the program
was still in operation.

Both the former analyst's account and the rising concern among some
members of Congress about the N.S.A.'s recent operation are raising
fresh questions about the spy agency.

Representative Rush Holt, Democrat of New Jersey and chairman of the
House Select Intelligence Oversight Panel, has been investigating the
incidents and said he had become increasingly troubled by the agency's
handling of domestic communications.

In an interview, Mr. Holt disputed assertions by Justice Department and
national security officials that the overcollection was inadvertent.

"Some actions are so flagrant that they can't be accidental," Mr. Holt
said.

Other Congressional officials raised similar concerns but would not
agree to be quoted for the record.

Mr. Holt added that few lawmakers could challenge the agency's
statements because so few understood the technical complexities of its
surveillance operations. "The people making the policy," he said, "don't
understand the technicalities."

The inquiries and analyst's account underscore how e-mail messages, more
so than telephone calls, have proved to be a particularly vexing problem
for the agency because of technological difficulties in distinguishing
between e-mail messages by foreigners and by Americans. A new law
enacted by Congress last year gave the N.S.A. greater legal leeway to
collect the private communications of Americans so long as it was done
only as the incidental byproduct of investigating individuals
"reasonably believed" to be overseas.

But after closed-door hearings by three Congressional panels, some
lawmakers are asking what the tolerable limits are for such incidental
collection and whether the privacy of Americans is being adequately
protected.

"For the Hill, the issue is a sense of scale, about how much domestic
e-mail collection is acceptable," a former intelligence official said,
speaking on condition of anonymity because N.S.A. operations are
classified. "It's a question of how many mistakes they can allow."

While the extent of Congressional concerns about the N.S.A. has not been
shared publicly, such concerns are among national security issues that
the Obama administration has inherited from the Bush administration,
including the use of brutal interrogation tactics, the fate of the
prison at Guantánamo Bay, Cuba, and whether to block the release of
photographs and documents that show abuse of detainees.

In each case, the administration has had to navigate the politics of
continuing an aggressive intelligence operation while placating
supporters who want an end to what they see as flagrant abuses of the
Bush era.

The N.S.A. declined to comment for this article. Wendy Morigi, a
spokeswoman for Dennis C. Blair, the national intelligence director,
said that because of the complex nature of surveillance and the need to
adhere to the rules of the Foreign Intelligence Surveillance Court, the
secret panel that oversees surveillance operation, and "other relevant
laws and procedures, technical or inadvertent errors can occur."

"When such errors are identified," Ms. Morigi said, "they are reported
to the appropriate officials, and corrective measures are taken."

In April, the Obama administration said it had taken comprehensive steps
to bring the security agency into compliance with the law after a
periodic review turned up problems with "overcollection" of domestic
communications. The Justice Department also said it had installed new
safeguards.

Under the surveillance program, before the N.S.A. can target and monitor
the e-mail messages or telephone calls of Americans suspected of having
links to international terrorism, it must get permission from the
Foreign Intelligence Surveillance Court. Supporters of the agency say
that in using computers to sweep up millions of electronic messages, it
is unavoidable that some innocent discussions of Americans will be
examined. Intelligence operators are supposed to filter those out, but
critics say the agency is not rigorous enough in doing so.

The N.S.A. is believed to have gone beyond legal boundaries designed to
protect Americans in about 8 to 10 separate court orders issued by the
Foreign Intelligence Surveillance Court, according to three intelligence
officials who spoke anonymously because disclosing such information is
illegal. Because each court order could single out hundreds or even
thousands of phone numbers or e-mail addresses, the number of individual
communications that were improperly collected could number in the
millions, officials said. (It is not clear what portion of total court
orders or communications that would represent.)

"Say you get an order to monitor a block of 1,000 e-mail addresses at a
big corporation, and instead of just monitoring those, the N.S.A. also
monitors another block of 1,000 e-mail addresses at that corporation,"
one senior intelligence official said. "That is the kind of problem they
had."

Overcollection on that scale could lead to a significant number of
privacy invasions of American citizens, officials acknowledge, setting
off the concerns among lawmakers and on the secret FISA court.

"The court was not happy" when it learned of the overcollection, said an
administration official involved in the matter.

Defenders of the agency say it faces daunting obstacles in trying to
avoid the improper gathering or reading of Americans' e-mail as part of
counterterrorism efforts aimed at foreigners.

Several former intelligence officials said that e-mail traffic from all
over the world often flows through Internet service providers based in
the United States. And when the N.S.A. monitors a foreign e-mail
address, it has no idea when the person using that address will send
messages to someone inside the United States, the officials said.

The difficulty of distinguishing between e-mail messages involving
foreigners from those involving Americans was "one of the main things
that drove" the Bush administration to push for a more flexible law in
2008, said Kenneth L. Wainstein, the homeland security adviser under
President George W. Bush. That measure, which also resolved the long
controversy over N.S.A.'s program of wiretapping without warrants by
offering immunity to telecommunications companies, tacitly acknowledged
that some amount of Americans' e-mail would inevitably be captured by
the N.S.A.

But even before that, the agency appears to have tolerated significant
collection and examination of domestic e-mail messages without warrants,
according to the former analyst, who spoke only on condition of
anonymity.

He said he and other analysts were trained to use a secret database,
code-named Pinwale, in 2005 that archived foreign and domestic e-mail
messages. He said Pinwale allowed N.S.A. analysts to read large volumes
of e-mail messages to and from Americans as long as they fell within
certain limits — no more than 30 percent of any database search, he
recalled being told — and Americans were not explicitly singled out in
the searches.

The former analyst added that his instructors had warned against
committing any abuses, telling his class that another analyst had been
investigated because he had improperly accessed the personal e-mail of
former President Bill Clinton.

Other intelligence officials confirmed the existence of the Pinwale
e-mail database, but declined to provide further details.

The recent concerns about N.S.A.'s domestic e-mail collection follow
years of unresolved legal and operational concerns within the government
over the issue. Current and former officials now say that the tracing of
vast amounts of American e-mail traffic was at the heart of a crisis in
2004 at the hospital bedside of John Ashcroft, then the attorney
general, as top Justice Department aides staged a near revolt over what
they viewed as possibly illegal aspects of the N.S.A.'s surveillance
operations.

James Comey, then the deputy attorney general, and his aides were
concerned about the collection of "meta-data" of American e-mail
messages, which show broad patterns of e-mail traffic by identifying who
is e-mailing whom, current and former officials say. Lawyers at the
Justice Department believed that the tracing of e-mail messages appeared
to violate federal law.

"The controversy was mostly about that issue," said a former
administration official involved in the dispute.