Matthew Olson -- NSA Matthew Olson A group of Senators questioned the general attorney for the National Security Agency Tuesday about whether U.S. intelligence agencies are using cell phone geo location data to track U.S. citizens without their knowledge.

According to The Wall Street Journal, the leader of the National Counterterrorism Center Matthew Olson told the Senate Select Committee on Intelligence that: "There are certain circumstances where that authority may exist."

The response came after repeated questions by Sen. Ron Wyden (D., Ore) whether the government has authority to “use cell site data to track the location of Americans inside the country.”

Olson admitted the possibility, said "it's a very complicated question," and told the committee the intelligence community is working on a memo to better answer the question.

The letter will be presented at the committees next hearing in September.