North Korea denies hacking Sony, U.S. stands by its assertion

By Jack Kim and Steve Holland SEOUL/WASHINGTON (Reuters) - North Korea said on Saturday U.S. accusations that it was involved in a cyberattack on Sony Pictures were "groundless slander" and that it wanted a joint investigation into the incident with the United States. An unnamed spokesman of the North's foreign ministry said there would be serious consequences if Washington refused to agree to the probe and continued to accuse Pyongyang, according to North Korea's U.N. missio