The White House says it is taking seriously a new threat by North Korea against its southern neighbor.
At the same time, the White House said Saturday's statement continued a pattern of "bellicose rhetoric" by North Korea.
The communist north warned the democratic south that their shared peninsula had entered a, quote, "state of war."
Analysts note that the Korean Peninsula has remained in a technical state of war for 60 years and say an all-out conflict is unlikely. But continued threats by the North against the South Korean government and the U.S. have raised fears that a misjudgment between the sides could result in a clash.
The White House said the U.S. is fully prepared and capable of defending its interests and allies in the region.