Recently, a new document leaked by the Former NSA Contractor "Edward Snowden" specify that The National Security Agency has technology capable of recording all the phone calls of an entire country and replaying them later. The Washington Post reported that, NSA collects the 100 percent of the users call through out the country.
In the initial deployment, collection systems are recording “every single” conversation nationwide, storing billions of them in a 30-day rolling buffer that clears the oldest calls as new ones arrive, according to a classified summary
As per the report, its is said that with the request of US officials, it withheld the details of the any users can be used to identify the country where the system is being used.
Snowden says that, the tools is much accurate and the program are most powerful then any other NSA program by allowing the spy agency to tap into the entire network from a country.