PRISM and another government phone surveillance program were made public last week, prompting the U.S. Senate Appropriations Committee to invite the director of the National Security Agency (NSA) Keith Alexander to testify on Wednesday.
According to General Alexander, the surveillance programs were able to thwart "dozens" of terror attacks in recent years, and could have event prevented the attacks on 9/11 if the program had been active before that fateful day.
"When I say 'dozens,' what I'm talking about here is that these authorities complement each other in helping us identify terrorist actions and help disrupt them," he testified in the online streamed hearing. "They complement each other."
The exact number of NSA-foiled attacks will likely be released next week, according to his statements.
In a more heated moment during the two-hour-long hearing, Sen. Jeff Merkley (D-Oreg.), a Verizon customer, gestured his cell phone in the air and asked, "What authorized investigation gave you the grounds for acquiring my cellphone data?"
Sen. Barbara Mikulski (D-Md.), the committee chairman gave the general further opportunities to open up, and explain the programs in details.
"Many of us are concerned about what is the access to people and businesses' information," she said. "There are those, because of the Snowden revelation, who would wonder about the government's access to that information."
Alexander struggled to answer a few of the senators questions, citing the sensitivity of the program, raising more questions about how the two programs, PRISM and the Verizon phone surveillance, really operate.
"I would rather take a public beating, and let people think I'm hiding something," he said. "Than jeopardize the security of this country."
PRISM is justified under Section 702 of the 2008 FISA Amendments Act and corresponds to the collection of data of people's Internet searches outside of the United States, according to the Guardian.
The other is justified under Section 215 of the Patriot Act, and collects information such as time stamps call duration, and geo-data from people's phone calls believe to just be Verizon telecommunication subscribers, reported the European publication.
"The reality is, they work together," Alexander said.
