North Korea's official Twitter account was apparently hacked on the birthday of Kim Jong-il's youngest son and heir apparent, Kim Jong-un.

South Korea's Yonhap news agency reported that the apparent hacking left four derogatory tweets about the Kim clan on the page Saturday morning.

"Let's create a new world by rooting out our people's sworn enemy Kim Jong-il and his son Kim Jong-un!" one tweet read.

Another called for an uprising to slay the Kims "with a sword."

Another said that ousting the dynasty would lead North Koreans to live "as happily as South Koreans."

Pyonyang launched the Twitter account, @uriminzok, in August to post a string of tweets glorifying the "Dear Leader" and regime. The feed has about 1,300 tweets and more than 11,000 followers.

North Korea keeps tight controls on its people when it comes to accessing information, but operates its own Twitter, Facebook and YouTube pages.

It was unknown where the tweets originated from. To defame the leadership is a crime punishable by death in North Korea.