Surveillance efforts helped bust terror plots: NSA

The US National Security Agency and justice department mounted a strong defense of the surveillance efforts of the government yesterday, with NSA chief general Keith Alexander claiming they had helped prevent "potential terrorist events" over 50 times since 9 / 11.

The officials claimed, the programmes protected US citizens from unwarranted intrusion, as they started shedding light on the scope of the secretive effort, in a rare public hearing.

A top FBI official claimed as he disclosed new details, that the efforts helped bust a plot to bomb the New York Stock Exchange. According to FBI deputy director Sean Joyce, NSA officials discovered the scheme, as they monitored a known extremist in Yemen, who was in contact with an individual in the US. After initiating surveillance, according to Joyce, they were able to detect "nascent plotting" to bomb the stock exchange and ultimately foil the plot.

Joyce also discussed another case in which the NSA used the programme to tip off the FBI about an individual's "indirect contacts" with terrorists overseas, which too ended in disrupted the activity, though he offered no detail.

The two cases had not been previously discussed by the administration. Joyce further confirmed prior claims that the programme helped detect information about the 2009 plot to bomb the New York subway system and a plot involving a Chicago resident to bomb a Danish newspaper.

Alexander described four thwarted plots, including a plan to bomb the New York subway, which he described as "the first core Al-Qaeda plot since 9/11, directed from Pakistan."

Joyce and others, defending the digital snooping, insisted that it had kept the US safe since 2001, but which had come under global criticism following leaks of classified details.

"In recent years, the information gathered from these programs provided the US government with critical leads to help prevent over 50 potential terrorist events in more than 20 countries around the world," Alexander said. He added least 10 threats were "homeland-based."

He told the House Intelligence Committee that most details were classified and would not be made public.

According to Joyce, a tip from the NSA, which had traced international phone calls from terror suspects to Kansas City, had led the FBI to obtain a court order to begin electronic surveillance on Khalid Ouazzani.

FBI agents after determining that Ouazzani had provided information and support for a "nascent" plot to bomb the NYSE, arrested him along with co-conspirators. Ouazzani pleaded guilty to conspiring to provide material support to Al-Qaeda in May 2010, but the FBI did not make any mention of a plot to bomb the stock exchange at the time.