The National Security Agency has a system that allows officials to record "100 percent" of the phone calls in a foreign country and rewind and review those conversations for up to 30 days, according to a report published Tuesday.
Officials confirmed the revelations about the MYSTIC program to The Washington Post, which learned about it through documents provided by former NSA contractor Edward Snowden.
According to the report, the NSA in 2009 created the voice interception program, which uses a tool enabling “retrospective retrieval" of the calls.
The United States used it against its “first target nation” in 2011, the Post says. Documents from 2013 suggest the program already has, or will be, extended to other nations.
The paper said it agreed to withhold information that could be used to identify the first targeted country.
The administration might be using these eavesdropping tools on as many as six other countries, the Post notes.
Out of billions of phone calls being recorded, the Post reports only 1 percent of the calls are analyzed.
A rolling buffer is used to clear the oldest phone calls to make way for new ones, allowing the NSA to “retrieve audio of interest that was not tasked at the time of the original call.”
Other intelligence agencies have access to the program as well, the report says.
The program appears to stand in contrast to other intelligence-gathering tools the NSA employs, as this one actually monitors the content of calls. Other documents provided by Snowden, for instance, have detailed the scope of the agency’s metadata program, which collects phone numbers among other data.
The report comes about two months after President Obama announced reforms to the NSA’s spying operations. Some of those changes included limiting the U.S.’s ability to retain and search communications between Americans and foreign citizens.
Obama said the U.S. would not monitor the communications of allies' leaders unless there is a “compelling national security purpose.”
The NSA would not, Obama suggested, spy on foreign citizens.
“Now let me be clear: our intelligence agencies will continue to gather information about the intentions of governments – as opposed to ordinary citizens – around the world, in the same way that the intelligence services of every other nation does,” he said in his speech in January.
A slew of reports from foreign news outlets last fall suggested the NSA had spied on foreign citizens or its leaders in countries such as France, Spain, Germany, Mexico and Brazil.