Wikileaks founder Julian Assange didn't mince words when he called Facebook an appalling spy machine.

Assange, the creator of the site that has leaked confidential government and business documents, heavily criticized the social network in an interview with Russian news site RT. He said Facebook lends itself to being pressured by U.S. intelligence authorities because of the amount of data it has on people.

Facebook in particular is the most appalling spying machine that has ever been invented. Here we have the world's most comprehensive database about people, their relationships, their names, their addresses, their locations and the communications with each other, their relatives, all sitting within the United States, all accessible to U.S. intelligence, Assange said.

He didn't stop there. He also called out Google and Yahoo! along with Facebook, saying the companies have built-in interfaces for U.S. intelligence.

It's not a matter of serving a subpoena. They have an interface that they have developed for U.S. intelligence to use, Assange said. Everyone should understand that when they add their friends to Facebook, they are doing free work for United States intelligence agencies in building this database for them.

Facebook took issue with these comments, saying it has a dedicated team of Certified Information Privacy Professionals overseen by two former federal cybercrime prosecutors that manage government requests.

We don't respond to pressure, we respond to compulsory legal process. There has never been a time we have been pressured to turn over data -- we fight every time we believe the legal process is insufficient. The legal standards for compelling a company to turn over data are determined by the laws of the country, and we respect that standard, a Facebook spokesperson said in a statement.

Facebook was actually one of the companies that backed Wikileaks last year, after many other companies, like PayPal and Mastercard, backed off its support. Facebook said its Wikileaks fan page did not violate any of its rules and regulations.

Google and Yahoo! did not respond to inquiries for comment.

Follow Gabriel Perna on Twitter at @GabrielSPerna