Sen. Bob Corker (R., Tenn.) told Fox News Sunday even he was not sure to what extent the National Security Agency kept tabs on Americans, adding he wanted the NSA to brief Congress "from top to bottom" to explain the programs in place and help ensure appropriate oversight.

CHRIS WALLACE: Let me ask you a direct question, sir. As the top Republican on Senate Foreign Relations, as you sit here today, do you feel you actually know what the government is and isn't doing in surveilling Americans?

CORKER: No. I don't think there are many people work that harder than I do. I'm not on the intelligence committee. Obviously, they are privy to information that I am not. But absolutely not. That's why I wrote a letter this week to the president, ask that the head of this organization come in and brief folks from top to bottom to explain every program that's under way, understand so we can understand its intent and to understand how appropriate oversight is taking place. Look, I appreciate efforts to keep Americans secure. At the same time, this is in front of us. We are not in front of it. Every day there are stories, as you just mentioned, that are leaked out. The American people want to know that those of us who are elected, Eliot and I, understand fully what's happening here. I don't think we do. I would imagine there are even members of the intelligence committee themselves that don't fully understand the gamut of things that are taking place. It's our responsibility to know those things, to ensure they're in balance, and I hope as soon as we get back there'll be a full briefing from top to bottom so that can happen.