If you thought the National Security Agency, which is now famous for collecting U.S. phone records or "metadata," wasn't at least capable of listening in on the actual content of phone calls, think again. A new Washington Post report says the NSA has the capability to record phone calls and hold on to the entire record on a 30-day basis -- for entire countries.

The report, published by the Washington Post, is based on top-secret documents leaked by ex-NSA contractor Edward Snowden and interviews with anonymous officials. It details the NSA's "MYSTIC" surveillance program, which can record "100 percent" of a foreign country's telephone calls and hold on to it for later retrieval.

To play back a specific all from the huge database of voice recordings, the NSA reportedly has a tool called "RETRO," which acts as a kind of DVR for the targeted nation's phone calls -- which "can replay the voices from any call without requiring that a person be identified in advance for surveillance," wrote WaPo. The tool keeps a rolling, auto-deleting 30-day database of phone call recordings, allowing the NSA a full month to search and listen in on any phone call from within a foreign nation targeted by MYSTIC.

MYSTIC, the recording side of the operation, began in 2009, while the RETRO tool only became fully operational in 2011, according to the report. Because MYSTIC is the very definition of bulk collection, it would be absurd to think NSA analysts could actually listen to all of the calls collected, and according to WaPo, only "a fraction of 1 percent" of the calls are actually played back. However, each month, analysts send millions of cuts from phone conversations for processing and long-term storage, the report says.

This newly reported surveillance capability by the NSA flies in the face of recent pledges by President Obama on NSA reform that the agency wouldn't spy on ordinary people that aren't national security targets. It also likely contradicts NSA Director Gen. Keith Alexander's insistence that the NSA only collects phone records, or "metadata" of U.S. citizens -- as any U.S. citizen making a phone call within or to a targeted foreign nation is likely to be swept up in the broad collection.

But it's also technically impressive. Information Week spoke to a data storage expert (anonymously) who estimated that recording and storing the call volume from a country the size of Pakistan would require 12 petabytes of storage per month, or the equivalent of 12,000 terabytes. (NB: the Washington Post, deferring to requests from U.S. officials, specifically mentioned no targeted foreign country.) B

But reports going back as far as 2012 indicate that the NSA and Pentagon have been building a facility in Bluffdale, Utah capable of storing a "yottabyte" of data -- or 1 trillion terabytes, so huge that the next order of magnitude doesn't even have a theoretical name yet -- so anything is possible.

MYSTIC and RETRO are authorized under Presidential Executive Order 12333, and are reportedly intended only for use outside the U.S. The NSA declined to confirm or deny to the Washington Post any expansion plans or discuss criteria for any change to the program.