The whistle-blower website WiliLeaks says it has begun releasing more than 5 million e-mails from Stratfor Global Intelligence, a private U.S.-based firm providing strategic analysis.

WikiLeaks says on its website that the e-mails reveal the company's “web of informers, pay-off structure, payment-laundering techniques and psychological methods.” It says the e-mails also contain privileged information about the U.S. government's attacks on WikiLeaks founder Julian Assange and Stratfor's own attempts to subvert WikiLeaks.

Stratfor acknowledged early Monday that some of its e-mails were about to be published. It described the action by WikiLeaks as “a deplorable, unfortunate — and illegal — breach of privacy.”

WikiLeaks does not say how it obtained the e-mails. However, Stratfor earlier reported that its computers were hacked on at least two occasions in December. A secretive alliance of hackers known as Anonymous claimed responsibility for the attack at that time.

WikiLeaks says the e-mails date from July 2004 to December 2011 and include more than 4,000 e-mails mentioning WikiLeaks or Assange, who is currently fighting extradition from Britain to Sweden on sexual assault charges. Assange says he fears Sweden will turn him over to the United States for prosecution in connection with the publication of thousands of confidential U.S. diplomatic cables that were stolen in 2010.

WikiLeaks says Stratfor provides intelligence analysis to major U.S. defense contractors such as Lockheed Martin, Northrop Grumman and Raytheon. It says the company's clients also include the U.S. Department of Homeland Security, the U.S. Marines and the U.S. Defense Intelligence Agency.

It says the files show how Stratfor has recruited a global network of informants who are paid via Swiss bank accounts and pre-paid credit cards. It says the company's mix of covert and overt informants include government employees, embassy staff and journalists around the world.

Stratfor says some of the stolen e-mails may have been forged or altered to include inaccuracies. It says it will not comment on which of the messages are authentic and which are not.