“The government has filed a police report over a possible attack against the government’s website,” the government said in a statement.
“The system was overloaded because an external website redirected many internet users to a specific file on (the government website) www.regeringen.se,” it said.
The site was never entirely out of service but was difficult to access for nine hours overnight on Saturday, the government said. The site was running normally again on Sunday morning.
As well as combatting espionage and terrorism, the Security Service, Säpo, is responsible for ‘counter-subversion’, or protecting the constitution.
Under its counter-subversion remit, Säpo aims to prevent activities which use “violence or force to… influence the political institutions or authorities to make decisions in a given direction”.
There has been much speculation in Sweden that the attack was the work of hackers angered over Swedish authorities’ closure on Wednesday of The Pirate Bay, one of the world’s most popular websites for the illegal downloading of movies and music.
In several raids involving more than 50 police officers in several Swedish cities, some 200 servers were seized and three people were arrested. They were later released.
The Pirate Bay reopened on Saturday using servers in The Netherlands. Media have suggested that Swedish police acted at the behest of US authorities and Hollywood studios. Justice Minister Thomas Bodström has vehemently denied the allegations.
Prime Minister Göran Persson told TT on Sunday that he did “not want to speculate” about whether the attack on the government website was a response to The Pirate Bay’s closure.
The Swedish police service’s website was down on Friday after a hacker overloaded the system by redirecting internet users to the site. A 17-year-old told local media he launched the attack as revenge for Pirate Bay’s closure.
Pirate Bay provides instructions on how to share music and film files using links offered on the site, which attracts 1.5 million users throughout the world every day.
Sweden last year passed a law banning the sharing of copyrighted material on the Internet without payment of royalties, in a bid to crack down on free downloading of music, films and computer games.
Violators risk a maximum sentence of two years in prison.