Computer hackers from South and North Korea are waging an apparent propaganda battle in cyberspace, less than two months after their militaries traded artillery fire across the tense sea border.
Users of the South's popular website dcinside.com have claimed responsibility for hacking into the North's Twitter account and its official website, and leaving messages denigrating the ruling Kim family.
A separate and now deleted posting on YouTube showed a cartoon of Kim Jong-Un -- youngest son and heir apparent of leader Kim Jong-Il -- mowing down ordinary people in a fancy sports car.
It was apparently posted to mark Jong-Un's birthday Saturday.
Suspected North Korean hackers have retaliated for the website hacking with an attack on dcinside.com, a spokeswoman told AFP Monday.
The North last August made its foray into Twitter, using its account to link to stinging statements criticising the South and the United States on its official website (www.uriminzokkiri.com).
The communist country, which has attracted more than 11,500 followers on Twitter, also opened an account on YouTube as it ramped up online propaganda efforts.
The South's hackers last month sabotaged the official website with a 12-line acrostic poem -- purportedly in praise of the Kims but with the first letter of each line spelling out derogatory words about them.
Last week dcinside.com was temporarily paralysed by a massive DDOS (distributed denial of service) attack, the spokeswoman said.
"The DDOS attack started mounting on our website as soon as local media reported the claim by our users that they duped the North with the poem," she said.
"Come out, Jong-Il and Jong-Un! Let's fight!" dcinside.com said on its website Monday, referring to the North's leader and his youngest son and heir apparent.
"Our CEO updated the phrase himself, as we all suspect the North was behind the attack on our website last week," the spokeswoman said.
Users of dcsinside.com have apparently taken revenge by hacking the North's Twitter account, @uriminzok. One of four critical postings urges the military to "point guns towards traitor Kim Jong-Il wasting fortunes on nuclear and missile weapons instead of feeding his people".
The tweets could still be read Monday morning. The Uriminzokkiri website was out of service Sunday before resuming operations on Monday.
The dcinside.com spokeswoman said she could not confirm whether the website's users were behind the hacking attack on the North's Twitter account.
South Korea's Unification Ministry, Korea Communications Commission and National Intelligence Agency all declined to comment.
The North is believed to have an elite unit of hackers. Some South Korean officials suspect it was behind a major DDOS attack on 25 US and South Korean websites in July 2009.
Explore further: Snowden, Assange top bill at Texas tech gathering (Update)