Last summer, the Anonymous offshoot known as LulzSec announced it was retiring after 50 days of hacktivist attacks on targets ranging from Sony to the Central Intelligence Agency.

Now, following the arrests of some of the group’s most prominent members, a group of hackers has taken up the LulzSec banner and vowed to begin attacking sites under the name “LulzSec Reborn.”

The group’s first target was a dating site called militarysingles.com, which caters to members of the armed forces. The hacking group claims to have stolen 170,000 records from the Web site Sunday, subsequently posting users’ personal information online.

A representative from the Web site did not respond to a request for comment. But the CEO of the parent company told the Los Angeles Times that the company has put measures in place to secure its data. The executive, Robert Goebel, said the Web site had been down over the weekend and that he does not believe the site was actually hacked.

“Regardless of whether it was a true claim or false claim, we’re treating it as though it’s true just to be safe,” Goebel told the paper.

The hack may not be confirmed, but in a tweet on what appears to be the group’s Twitter feed, the hackers posted a link to a defaced Web page under the militarysingles.com domain name that references the group by name.

Several members of LulzSec and Anonymous who made a splash with attacks last year have been arrested in the United States and in Europe, as investigators move to crack down on the loosely organized hacking collective.

Far from discouraging the hackers, the arrests have prompted a new surge of attacks with targets ranging from the Pope to a Spanish security firm that reportedly worked with the Federal Bureau of Investigation to arrest the leaders of LulzSec.

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