North Korea has called US President Barack Obama a "monkey" over the ongoing cyber attacks and blamed Washington for the recent internet blackout.

The reclusive nation experienced an internet shutdown recently and was offline for nine and half hours, followed by frequent disruption.

"The United States, with its large physical size and oblivious to the shame of playing hide and seek as children with runny noses would, has begun disrupting the internet operations of the main media outlets of our republic," said Pyongyang's powerful National Defence Commission in a statement.

The commission added in the statement carried by the state-run Korean Central News Agency (KCNA): "Obama always goes reckless in words and deeds like a monkey in a tropical forest."

"Obama had better thrust himself to cleaning up all the evil doings that the US has committed out of his hostile policy against [North Korea] if he seeks peace on US soil. Then all will be well."

The war of words between Washington and Pyongyang has been intensifying ever since the hacking attack on Sony Pictures. The US blames North Korea for the cyber attack on Sony Pictures over the controversial movie "The Interview" but Pyongyang denies carrying out the attack.

Obama pledged a "proportionate response" after the Sony attack following which North Korea's internet went down. US officials have not owned up the attack and have evaded direct comments related to the outage.