United States (CNN)- The National Security Agency says it's deleting hundreds of millions of phone records collected since 2015.
They're called "call detail records," or CDR’s, and the files come from American telecommunications companies.
CDR’s record details of phone calls, but not their content.
NSA says it is deleting the files because it learned the agency isn't authorized to have some of them.The problem is, it doesn't know which ones those are, so all of the files have to go.
A former justice department official calls the purge a failure, while Senator Ron Wyden says it's the telecom companies that acted carelessly.
According to the New York Times, the NSA collects hundreds of millions of CDR’s each year.
That surveillance is allowed under the Freedom Act, which passed in 2015 after the Patriot Act expired.