WASHINGTON (AP) — The head of the National Security Agency sidestepped questions Thursday from a senator about whether the NSA has ever used Americans cellphone signals to collect information on their whereabouts that would allow tracking of the movements of individual callers.

Asked twice by Sen. Ron Wyden, D-Ore., if NSA had ever collected or made plans to collect such data, NSA chief Gen. Keith Alexander answered both times by reading from a letter provided to senators who had asked the same question last summer. He also cited a classified version of the letter that was sent to senators and said, “What I don’t want to do … is put out in an unclassified forum anything that’s classified.”