North Korea has warned of 'grave consequences' if the US refuses a joint probe on the cyber attack against Sony Pictures, the hermit kingdom's mouthpiece KCNA reported, according to Reuters' breaking news tweet.
North Korea further says that it can prove not being involved in the attack, and that a joint investigation with the US would be mandatory towards this end.
This followed the threat by North Korea to boost its nuclear capabilities after what it referred to as the "hostile" US plans to invade Pyongyang. This itself was a fall-out of a recommendation by UN members states on Thursday that North Korea be referred to the International Criminal Court for alleged human rights abuses.
The above proposal for joint probe came hours after FBI confirmed on Friday that North Korea was behind the cyber attacks on Sony Pictures.
The company scrapped the movie "The Interview"'s opening following a cyber attack blamed on North Korea. President Barack Obama has decried the action as a "mistake".
The company said on Friday that it was "surveying alternatives to enable us to release the movie on a different platform".
Obama said that Sony "made a mistake" succumbing to a force created by external sources.
"We cannot have a society in which some director some place can start imposing censorship on the United States," he said in a news conference, adding that Washington will respond to the cyber-attack in a "manner that we choose".
Responding to Obama's comments, Sony Pictures clarified that they had not made an error in pulling down the film.
"We have not caved, we have not given in, we have preserved and we have not backed down," Sony Pictures chief executive and chairman Michael Lynton told CNN.