LONDON — The loose-knit hacking movement "Anonymous" claimed Sunday to have stolen thousands of credit card numbers and other personal information belonging to clients of U.S.-based security think tank Stratfor. One hacker said the goal was to pilfer funds from individuals' accounts to give away as Christmas donations, and some victims confirmed unauthorized transactions linked to their credit cards.

LONDON — The loose-knit hacking movement "Anonymous" claimed Sunday to have stolen thousands of credit card numbers and other personal information belonging to clients of U.S.-based security think tank Stratfor. One hacker said the goal was to pilfer funds from individuals' accounts to give away as Christmas donations, and some victims confirmed unauthorized transactions linked to their credit cards.

Anonymous boasted of stealing Stratfor's confidential client list, which includes entities ranging from Apple Inc. to the U.S. Air Force to the Miami Police Department, and mining it for more than 4,000 credit card numbers, passwords and home addresses.

Austin, Texas-based Stratfor provides political, economic and military analysis to help clients reduce risk, according to a description on its YouTube page. It charges subscribers for its reports and analysis, delivered through the web, emails and videos. The company's main website was down, with a banner saying the "site is currently undergoing maintenance."

Proprietary information about the companies and government agencies that subscribe to Stratfor's newsletters did not appear to be at any significant risk, however, with the main threat posed to individual employees who had subscribed.

"Not so private and secret anymore?" Anonymous taunted in a message on Twitter, promising that the attack on Stratfor was just the beginning of a Christmas-inspired assault on a long list of targets.

Anonymous said the client list it had already posted was a small slice of the 200 gigabytes worth of plunder it stole from Stratfor and promised more leaks. It said it was able to get the credit card details in part because Stratfor didn't bother encrypting them — an easy-to-avoid blunder which, if true, would be a major embarrassment for any security-related company.

Fred Burton, Stratfor's vice president of intelligence, said the company had reported the intrusion to law enforcement and was working with them on the investigation.

Hours after publishing what it claimed was Stratfor's client list, Anonymous tweeted a link to encrypted files online with names, phone numbers, emails, addresses and credit card account details.

Companies that shared secret information with Stratfor in order to obtain threat assessments might worry that the information is among the 200 gigabytes of data that Anonymous claims to have stolen, he said.

"If an attacker is walking away with that much email, there might be some very juicy bits of information that they have," said Josh Shaul, chief technology officer of Application Security Inc., a New York-based provider of database security software.

Anonymous also linked to images online that it suggested were receipts for charitable donations made by the group manipulating the credit card data it stole.

"Thank you! Defense Intelligence Agency," read the text above one image that appeared to show a transaction summary indicating that an agency employee's information was used to donate $250 to a nonprofit.

One receipt — to the American Red Cross — had Allen Barr's name on it.

Barr, of Austin, Texas, recently retired from the Texas Department of Banking and said he discovered last Friday that a total of $700 had been spent from his account.

"It was all charities, the Red Cross, CARE, Save the Children. So when the credit card company called my wife she wasn't sure whether I was just donating," said Barr, who wasn't aware until a reporter with the AP called that his information had been compromised when Stratfor's computers were hacked.