North Korea proposed a joint investigation with the United States (US) on the cyber attack against Sony Pictures, calling the charge by the FBI that it was behind the attack "slander", state media said on Saturday.
An unnamed spokesman of the North's foreign ministry said there would be "grave consequences" if Washington refused to agree to the joint probe and continued to accuse the North, the official KCNA news agency reported.
Read: Barack Obama mocks absurd plot twist of cyberattack on Sony
