The Obama administration permitted the National Security Agency to collect vast amounts of email records for at least two years, according to the latest report from The Guardian.
Leaked documents show that the NSA was able to identify the email accounts that sent and received messages, as well as IP addresses, which can reveal the computer's location. The data collection did not include the contents of the emails.
The program was first started after the 9/11 terrorist attacks during the Bush administration and was brought under a legal framework in 2004, the newspaper reported. The Obama administration confirmed the existence of the program, but said it ended in 2011.
The NSA collected records in "bulk" for "communications with at least one communicant outside the United States or for which no communicant was known to be a citizen of the United States," according to an NSA inspector general report obtained by The Guardian.
The NSA also had the authority to "analyze communications metadata associated with United States persons and persons believed to be in the United States," according to a separate 2007 Justice Department memo.
The Guardian explained that the NSA used the program to study "the online records of people who communicated with people who communicated with targeted individuals."
A secret Foreign Intelligence Surveillance Act Court reviewed and approved the program every 90 days while it was operational, according to the newspaper.
The Obama administration has charged former intelligence analyst Edward Snowden with espionage for leaking other documents to The Guardian describing secret NSA surveillance programs. He is believed to be in Russia.
Those other programs included the vast collection of U.S. phone records and an Internet surveillance program.