The hacktivist collective group Anonymous claims to have walked away with thousands of credit card numbers and personal information from the high-profile clients of analytical intelligence agency Stratfor.

"#AntiSec plundered 200gb of their mails and more booty," read a tweet by @AnonymousIRC posted on Saturday.

The group also claims to have stolen $1 million from Stratfor as well as the company's confidential client list which includes Apple, the U.S. Air Force and the Miami Police Department. Anonymous has published two lists of credit card details containing numbers that have been used to donate large sums of money to organizations such as the American Red Cross and CARE. The group also warned that it will continue to commit more attacks in the next few days.

"#Antisec has enough targets lined up to extend the fun fun fun of #LulzXmas throught the entire next week," @AnonymousIRC tweeted.

In another statement Anonymous said, "Tomorrow, we will be dropping another enormous dump on our next target: the entire customer database from an online military and law enforcement supply store."

Lulz is a reference to Lulz Security another hacktivist group working with Anonymous. The attack on Stratfor is just the latest in a series of high-profile cyber attacks perpetrated by Anonymous this year. The group is allegedly behind the attacks on PayPal, Visa and Mastercard.

Anonymous claims it was able to steal the credit card data from Stratfor because the data was unencrypted and that many passwords were just the company's name.

"If Stratfor would give a s--- about their subscriber info they wouldn't store CC/CCV numbers in cleartext, with corresponding addresses," according to one tweet.

Stratfor maintains that the group didn't steal the company's confidential client list.

"Contrary to this assertion the disclosure was merely a list of some of the members that have purchased our publications and does not comprise a list of individuals or entities that have a relationship with Stratfor beyond their purchase of our subscription-based publications," the firm says in an e-mail to its members dated December 25 according to report from Computerworld.

Stratfor's website was still offline as of Tuesday morning. The company also warned public supporters on its Facebook page that they could be targeted by the hacker group. Stratfor has hired an identity theft and monitoring service to assist its members.