NSA says efforts have foiled plots; leaks causing a reassessment

The director of the National Security Agency said Wednesday that “dozens” of terrorist plots have been foiled as a result of a top-secret telecommunications surveillance program that has come under public scrutiny after a former contractor leaked information about it last week.

Army Gen. Keith B. Alexander said he would provide senators with precise figures “over the next week,” as he testified before the Senate Appropriations Committee. The general, who also heads U.S. Cyber Command, said he would discuss specific cases in more detail Thursday in a closed hearing on the NSA leak.

However, he did say the program known as Prism “developed the lead” for disrupting a New York City subway bomb plot by Afghan-American Najibullah Zazi in 2009.

Sen. Barbara A. Mikulski, Maryland Democrat and committee chairwoman, urged fellow senators to save their questions for Thursday’s closed hearing.

Still, senators continued to question Gen. Alexander about the program, asking how a low-level systems administrator without a high school diploma was able to access top secret information.

“I have grave concerns over that, the access that he had, the process that we did. And those are things that I have to look into and fix from my end and that, across the intel community, Director [of National Intelligence James R.] Clapper said we’re going to look across that as well. I think those absolutely need to be looked at,” said Gen. Alexander, adding that the contractor had “great skills” as a systems administrator.

The general also said the public needs to know how NSA’s programs operate amid growing concerns that government efforts to secure the nation are encroaching on Americans’ privacy and civil liberties.

“I do think it’s important that we get this right and I want the American people to know that we’re trying to be transparent here, protect civil liberties and privacy but also the security of this country,” he said.

Meanwhile in Hong Kong, the former contractor who leaked the classified information told the South China Morning Post newspaper that he is not trying to hide from justice. Edward Snowden, 29, said he hopes to use Hong Kong as a base to reveal misdeeds by the U.S. government.

Mr. Snowden, a former information technician for the contracting firm Booz Allen Hamilton, leaked a classified PowerPoint presentation about the NSA’s Prism program to Britain’s Guardian newspaper last week, revealing that the agency collects vast amounts of data about the phone and Internet communications of hundreds of millions of people.

In his interview with the South China Morning Post, Mr. Snowden said that he is “neither a traitor nor hero. I’m an American.” The newspaper posted excerpts of the interview with him on its website.

During the Senate hearing, Gen. Alexander warned that disclosures about the secret program have eroded agency capabilities and, as a result, U.S. allies and Americans won’t be as safe as they were two weeks ago.

“Some of these are still going to be classified and should be, because if we tell the terrorists every way that we’re going to track them, they will get through and Americans will die,” he said, adding that he would rather be criticized by people who think he’s hiding something “than jeopardize the security of this country.”

• This article is based in part on wire service reports.