The White House has said it is taking North Korea's latest statements about a "state of war" between the two Koreas "seriously," despite Pyongyang's history of "bellicose rhetoric."
Caitlin Hayden, a spokeswoman for the National Security Council, said Washington is in close contact with Seoul.
Earlier on March 30, Pyongyang said the armed force of North Korea have "entered into an actual military action" and that "inter-Korean relations have naturally entered a state of war."
The White House said the United States is fully prepared and capable of defending its interests and those of its allies in the region.
Based on reporting by AP and the "Christian Science Monitor"