U.S. secret services developed a spy program, capable of recording 100% of each and every phone call across entire nations. The Washington Post shares another bit of classified information referring to secret documents supplied by former NSA contractor Edward Snowden.

Previously reported surveillance system could track phone numbers, times and duration of calls. Now, MYSTIC is used to intercept phone conversations in one specific country, storing audio data for 30 days.

This NSA program dates to 2009, when by 2011 its RETRO tool, short for “retrospective retrieval”, was ready to be rolled-out at full capacity. Program's senior managers compared MYSTIC to a time machine, meaning voices from any call can be replayed without requiring the NSA to identify a person for surveillance in advance.

The National Security Agency has built a surveillance system capable of recording “100 percent” of a foreign country’s telephone calls, enabling the agency to rewind and review conversations as long as a month after they take place, according to people with direct knowledge of the effort and documents supplied by former contractor Edward Snowden.

A senior manager for the program compares it to a time machine — one that can replay the voices from any call without requiring that a person be identified in advance for surveillance. On Jan. 17, President Obama called for significant changes to the way the NSA collects and uses telephone records of U.S. citizens.