Harkin, however, added he is not on the Senate Intelligence Committee and is not made aware of some details of the programs.

Several national security officials along with lawmakers have said the NSA programs that collect data on phone calls and Internet use have stopped terrorist attacks.

"It's dozens of terrorist events that these have helped prevent, from my perspective," NSA chief Keith Alexander told the Senate Appropriations Committee on Wednesday.

Harkin said he had "deep concerns" about the programs and that there should be "really in-depth hearings" examining them. He added, according to the Register, that there were three problems related to the programs: the government had granted classified security clearance to too many people, the government had been too invasive into peoples' private lives and too much information had been classified as top-secret.