White House press secretary Jay Carney on Wednesday downplayed an ominous warning from the North Korean army that it had final approval to launch nuclear attacks against the United States.
On Wednesday, the Pentagon said it was moving an advanced missile defense system to Guam in response to nuclear threats from North Korea.
In a statement published by the North Korean state news agency and reported by AFP, a spokesman from the General Staff of the Korean People's Army warned that it would respond to American provocations with "cutting-edge smaller, lighter and diversified nuclear strike means."
"The merciless operation of (our) revolutionary armed forces in this regard has been finally examined and ratified," the statement continued, adding that the United States "had better ponder over the prevailing grave situation."
The White House warned such provocations would only further damage relations with the rest of the international community.
"It’s important to say that, in every instance, this refusal to abide by its international obligations and to engage in threats and provocative rhetoric and behavior only serves to isolate North Korea further, to make it more and more difficult for the North Korean economy to develop, and imposes more and more hardships on the North Korean people," Carney said.
The situation in the region has deteriorated in recent weeks, with Pyongyang announcing Wednesday that it had barred South Korean workers from a jointly run industrial zone on the border between the two countries.
That announcement came just a day after officials declared their intention to restart a shuttered nuclear reactor. North Korea has escalated tensions in recent weeks, declaring a "state of war" against South Korea and threatening to attack the United States.
North Korea's actions are thought to be driven by additional United Nations sanctions that resulted from its recent nuclear test. The United States has responded to Pyongyang's posturing with a series of military drills in the region, as well as a repositioning of naval ships in waters off the Korean peninsula.