The latest revelations from documents leaked by former National Security Agency contractor Edward Snowden showed that the American spy agency has secretly been collecting millions of email and chat contact lists around the world.
The Washington Post reported on the program Monday, citing anonymous senior intelligence officials who confirmed the existence of the program.
A counterterrorism effort aimed at monitoring connections around the globe, the program reportedly takes in as many as 500,000 contacts from email inboxes and chat rooms every day, The Post said.
The Post, citing an internal agency report, described an average day's gleaning as follows: "444,743 e-mail address books from Yahoo, 105,068 from Hotmail, 82,857 from Facebook, 33,697 from Gmail and 22,881 from unspecified other providers."
The NSA circumvented legal restrictions on data collection by doing it all overseas, but also compromised the contacts of many Americans, said The Post.
Two senior US intelligence officials acknowledged this fact, though they did not offer an estimate of how many Americans would have been affected.
More from GlobalPost: Brazil's NSA fury
A Google spokesperson told CNET in a statement, "We have neither knowledge nor participation in this mass collection of Web mail addresses or chat lists by the government."
Yahoo responded to the report with, "We are not aware of nor have we participated in the alleged mass collection of user data by the government."
Facebook pushed for greater transparency, while Microsoft denied providing unfettered access to the government and added, "We would have significant concerns if these allegations about government actions are true."
Alex Abdo, a lawyer with the American Civil Liberties Union, responded to the news Tuesday, writing to the Associated Press: "This revelation further confirms that the NSA has relied on the pretense of 'foreign intelligence gathering' to sweep up an extraordinary amount of information about everyday Americans."
However, a spokesman with the organization responsible for the NSA, the Office of the Director of National Intelligence, told the Post, "[w]e are not interested in personal information about ordinary Americans."
Earlier this year, Snowden leaked information to the press about top-secret US surveillance programs that gathered the phone records and online information of millions including American citizens, sparking widespread outrage.
In June, US President Barack Obama defended the NSA program collecting emails and internet data, saying it "does not apply to US citizens, and it does not apply to people living in the United States."
More from GlobalPost: Are we doomed to a national surveillance state?