US government websites taken down in hacking attacks

The Treasury Department, Secret Service, Federal Trade Commission and Transportation Department websites were all shut down for as long as two days after unknown parties carried out a denial of service (DOS) attack.

Amy Kudwa, spokeswoman for the Homeland Security Department, told Associated Press that the agency's US Computer Emergency Readiness Team issued a notice to federal departments and other partner organisations about the problems and " advised them of steps to take to help mitigate against such attacks".

The attacks have continued for more than three days, an unusual occurrence since most DOS attacks are usually short in duration.

Problems are still continuing on some sites, although most web pages are now up and running. The identity of the group behind the attack is not known but worryingly similar attacks also took place over the weekend in South Korea.

South Korean government agency sites, banks and Internet sites were hit in the attacks. Ahn Jeong-eun, a spokeswoman at the Korea Information Security Agency, said the US and South Korean attacks appeared to be linked.

Over the past few years, DOS attacks have been increasingly used as a form of protest and disruption to mirror real world conflicts. The first large scale example of this came in Estonia but similar cases have been seen in Georgia.

The EU is to set up a special task force to deal with such attacks against member states and NATO is also preparing for traditional warfare to move online.