Frustrated online gamers trying to slow their opponents as well as Wikileaks have now been blamed for the cyber attack that disrupted more than 1200 Web sites, including some in Australia, last week.

The massive denial-of-service attack was launched via thousands of Internet-connected devices. It overwhelmed servers at Dynamic Network Services or Dyn, which connects users to Web sites.

Several Internet security experts claim a group of disaffected videogame players dubbed the Lizard Squad carried out the attack, using computer instructions refined from video gaming code.