The NSA has repeatedly denied that it tracks cellphone location data as part of its broad surveillance efforts. But today The New York Times reports that the agency has secretly tested such bulk data collection — and it's done so on more than one occasion. A pilot program allegedly ran in 2010 and again the following year. These tests involved actual data samples from American wireless customers and were intended "to test the ability" of the NSA's systems to handle the resulting data format, according to the report. The number of US citizens unknowingly involved in the pilot isn't clear, nor has the NSA said whether it still possesses the resulting data.

"That data was not used for any other purpose and was never available for intelligence analysis purposes," reads a draft answer written for intelligence director James Clapper ahead of his appearance before the Senate Judiciary Committee today. The Times obtained Clapper's written answer in advance of the hearing. The agency ultimately decided against pursuing location tracking further, but Clapper's prepared response offers little else in terms of specifics.

The issue came under renewed scrutiny last week after Senator Ron Wyden asked NSA director General Keith Alexander whether the agency had ever collected such location data in bulk. Alexander denied that the NSA receives cell-site information under the Patriot Act and said the agency "has no current plans to do so." But he added that classified data given to the Senate Intelligence Committee would offer "additional detail" on the matter, raising concerns that the NSA monitors location through some other legal justification. Wireless carriers have the ability to track your every movement, and today's news confirms that the NSA has at least experimented with taking advantage of that.