Just minutes after the U.S. Department of Justice repossessed the domains of Megaupload, Megavideo, Megaporn and a collection of other popular filesharing sites, the hacker collective Anonymous got to work on a few takedowns of its own.

On Thursday afternoon, Anonymous claimed credit for cyberattacks that knocked offline the websites of the U.S. Department of Justice, Recording Industry of America, Motion Picture Association of America and Universal Music. The so-called denial of service attacks that overwhelmed those sites with junk traffic came less than an hour after the Justice Department announced the takedown of the Mega sites, along with the arrest of former hacker and Mega founder Kim Dotcom and six others, who are being indicted on charges of copyright infringement and money laundering.