N. Korea slams 'hostile' US sanctions over Sony hack

North Korea on Sunday lashed out at fresh sanctions imposed by the United States in retaliation for its alleged cyber attack on Sony Pictures, criticising Washington for refusing a proposed joint investigation. US President Barack Obama last week authorised a new layer of sanctions on several Pyongyang institutions and officials, in the wake of the crippling hacking attack on the Hollywood movie studio. "The persistent and unilateral action taken by the White House to slap 'sanctions&#