Unidentified hackers paralyzed leading Korean and international websites for a third day Thursday. Starting at 6 p.m., the websites of the Chosun Ilbo, Kookmin Bank, the e-mail services of web portals Naver, Daum and Paran, the government's G4C electronic civil appeals network and the homepage of e-commerce service provider Auction saw continued attacks that paralyzed them or drastically slowed connection speeds.

According to computer security firm AhnLab, the current attack began on July 4, Independence Day by U.S. time or at around 2 a.m. on July 5 Korean time. After a primary attack on the White House website and those of other U.S. government agencies, the targets shifted to Cheong Wa Dae, the National Assembly, the Chosun Ilbo, Naver and other Korean sites in the second to fourth waves of attacks. Police say the nearly identical tactics used in the attacks show that all four of them were committed by the same perpetrators.

Intelligence officials say they have yet to find technical proof, but circumstantial evidence shows it is almost certain that North Korea is behind the attacks. They add that North Korea's Committee for Peaceful Reunification of the Fatherland, which is in charge of dealing with South Korea, in an announcement on June 27 seemed to hint at an impending cyber attack. More evidence is that the communist country launched seven short-range missiles on the U.S. Independence Day, and that the cyber attacks were timed to take place on the 15th anniversary Wednesday of the death of former North Korean leader Kim Il-sung. AP and Fox News also quoted unnamed Defense Department officials as saying that North Korea was behind the latest cyber attacks.

But Korean computer security firm Shiftworks cast doubt on the claim, saying a probe of the IP address tracked the attacker to the United States.