The nation's top diplomat for US affairs warned a vicious showdown could erupt if the US and South Korea hold annual war games as planned next month.
Han Song Ryol said America's decision to place Kim Jong-Un on the sanctions list for the first time for sickening crimes including torture and execution could put the super powers on war footing.
He said: "The Obama administration went so far to have the impudence to challenge the supreme dignity of the DPRK in order to get rid of its unfavorable position during the political and military showdown with the DPRK.
"The United States has crossed the red line in our showdown. We regard this thrice-cursed crime as a declaration of war."