The United States warned North Korea against provocations Tuesday, using a standard linguistic formula to shrug off Pyongyang's threat to scrap the armistice which ended the Korean war.
North Korea's latest saber-rattling came hours before the United States and China made a joint call for tightened sanctions on the isolated state following its third nuclear test on February 12.
"The DPRK will achieve nothing by threats or provocations which will only further isolate North Korea," White House spokesman Jay Carney said, calling Pyongyang's latest threats not new and helpful.
North Korea earlier threatened to scrap the armistice, which dates from 1953, citing US moves to impose sanctions for its nuclear test and tensions over South Korean-US military exercises.
The North's military said it could launch a "precise" strike anytime, unrestrained by the armistice. It also warned it could mount a strike with atomic weapons to counter any US nuclear threat.
In a statement on official media, the military called the joint exercise a "most blatant" provocation and slammed a "vicious" scheme by the US and its allies to push for tougher United Nations sanctions.
The armistice will be "completely" nullified from March 11, when the South Korean-US exercise gets into full swing in the South, the North said.