The U.S Department of State and a number of Swedish government websites were among those forced offline in an apparent mass DDoS (Distributed Denial of Service) attack.

The websites for the Swedish Armed Forces, Courts Administration, and the Swedish Institute (an initiative to promote the country around the world) were among those affected.

The person behind the Twitter account @TheWikiBoatBR (who does not appear to have an explicit association with Anonymous) posted a string of tweets suggesting responsibility for several attacks. Among those targeted were the Department of State, U.S. Department of Education, Sony, and Harvard University. The State Department site was still offline at the time of publication.

A DDoS attack is one in which a website’s servers are overloaded by a vast number of systems trying to access them, which often forces the site offline.

Swedish Armed Forces Communications and Public Affairs representative Therese Fagerstedt told The Local that it was not clear who was responsible, but it appears the DDoS may have been carried out to protest the charges laid against WikiLeaks founder Julian Assange.

Prosecutors in Sweden want to charge Assange over alleged sex crimes. He has taken refuge at Ecuador’s London embassy since June, and has been granted asylum by Ecuador.

The #OpFreeAssange hashtag, the same one used by Anonymous to discuss actions against the websites of Interpol and U.K. government websites in recent weeks, was used to talk about the Sweden attacks on Twitter.

Photo of U.S Secretary of State Hillary Clinton by Medill DC/Flickr