"Anonymous Korea" claimed to take down several North Korean state websites Saturday, just hours after North Korea said it has entered into a "state of war" with South Korea.

North Korea's main official state website was back up and running, as of 5 p.m. Eastern Time on Saturday. But Mashable was still unable to access three of the five listed websites that Anonymous Korea claimed to have attacked.

The attacks appear to be as part of an online hacking effort dubbed "#OpNorthKorea."

Uriminzokkiri, a North Korean news and propaganda site, was also back up after a reported hack.

The site for North Korea's official central news agency appeared unaffected Saturday.

SEE ALSO: Cyberattacks Legal Under the Laws of War

Saturday's cyberattacks against North Korea also happened just a day after the country claimed to have rockets aimed at U.S. targets.

Earlier this month, South Korean officials suspected that North Korea may have instigated attacks agains three banks and two broadcasters, The New York Times reported.

Update, 3:45 p.m. ET:

While Anonymous Korea took credit for Saturday’s attacks, a self-proclaimed “hactivist for good” – known as The Jester – claimed they hijacked his efforts:

Yawn. Anonymous hijacking my gig again. mashable.com/2013/03/30/ano… << Umm I'm pretty sure it was me, because I was there when I did it. — JΞSTΞR™(@th3j35t3r) March 30, 2013

Using a justification that "there is an unequal amount of good and bad in most things," The Jester has previously claimed responsibility for hacking WikiLeaks, 4chan and Jihadist websites. He claims to obstruct “the lines of communication for terrorists, sympathizers, fixers, facilitators, oppressive regimes and other general bad guys.”

Graphic via iStockphoto, Lepro, composite by Charlie White/Mashable