NSA director: Programs disrupted dozens of attacks, "We just can't name one".

WASHINGTON (AP) — The director of the National Security Agency vigorously defended once-secret surveillance programs as an effective tool in keeping America safe, telling Congress on Wednesday that the information collected disrupted dozens ofterrorist attacks without offering details.

In his first congressional testimony since revelations about the top-secret operations, Army Gen. Keith Alexander insisted that the public needs to know more about how the programs operate amid increasing unease about rampant government snooping and fears that Americans' civil liberties are being trampled.

"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," Alexander told a Senate panel.

He described the steps the government takes once it suspects a terrorist organization is about to act — all within the laws approved by Congress and under stringent oversight from the courts. He said the programs led to "disrupting or contributing to the disruption of terrorist attacks," but he did not give details on the terror plots.

Half a world away, Edward Snowden, the former contractor who fled to Hong Kong and leaked documents about the programs, said he would fight any U.S. attempts to extradite him. American law enforcement officials are building a case against him but have yet to bring charges.

"I am not here to hide from justice; I am here to reveal criminality," Snowden said of the surveillance programs in an interview with the South China Morning Post.

In plain-spoken, measured tones, Alexander answered senators' questions in an open session and promised to provide additional information to the Senate Intelligence Committee in closed session on Thursday. The director of national intelligence has declassified information on two thwarted attacks — one in New York, the other in Chicago — and Alexander said he was pressing for more disclosures.

But he also warned that revelations about the secret programs have eroded agency capabilities and, as a result, the U.S. and its allies 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."

Alexander said he was seriously concerned that Snowden, a former employee with Booz Allen Hamilton, had access to key parts of the NSA network, a development that demands a closer examination of how well the agency oversees contract employees.

Alexander said Snowden was a system administrator who didn't have visibility into the whole NSA network but could access key portions of it.