ST. PAUL (WCCO) — US Sen. Al Franken, D-Minn., says he’s not surprised by revelations that federal security agencies collect phone and computer data on American citizens.

The National Security Agency secretly gathered personal data on Americans since 2007, including their internet use and cell phone service. It’s something Franken says he “was very well aware of.”

“I can assure you, this is not about spying on the American people,” Franken said.

Franken, who sits on the Senate Judiciary Committee, says he got secret security briefings on the program and he says it prevented unspecified terrorist acts.

“I have a high level of confidence that this is used to protect us and I know that it has been successful in preventing terrorism,” Franken said.

Franken’s comments come one day after a former U.S. government intelligence worker, named Edward Snowden, identified himself as the person responsible for leaking documents about the program to a British Newspaper.

Minnesota Congressman Keith Ellison told ABC News he has deep concerns and that very few members of Congress knew the extent of the secret surveillance.

“We need to peel it back and we need to make sure congress is considering the constitution when we write these laws,” Ellison said.

But Franken defends the secrecy of the program, saying the government is trying to strike a delicate balance between public right to safety and the public right to privacy.

“There are certain things that are appropriate for me to know that is not appropriate for the bad guys to know,” Franken said.

Franken said he believes it’s proper for the Justice Department to investigate the government worker who leaked the existence of the NSA program.

However, Franken did not answer our question on whether he thought the leaker should be extradited from Hong Kong and prosecuted.