“The official site, regeringen.se, was offline for several hours overnight and only a message saying the site could not be reached was visible.
Commercial websites including Visa, MasterCard and PayPal have already been targeted by co-ordinated action on one of the busiest shopping days of the year after the firms said that they would no longer process donations to WikiLeaks.
A group calling itself Anonymous and operating under the banner ‘Operation Payback’ was behind some of the attacks and there were concerns that Twitter could become a target because it removed Anonymous’ listing. “
(Source: WikiLeaks cyberwar: hackers bring down Swedish government site – Telegraph)