North Korea is deepening its isolation from the international community with threats and saber-rattling, the White House said on Wednesday after Pyongyang threatened to attack the South for joining a US-led vessel inspection system.
"My sense is that they're trying to get renewed attention," said White House spokesman Robert Gibbs.
Meanwhile, US Secretary of State Hillary Clinton reaffirmed on Wednesday US commitments to allies Japan and South Korea in the face of North Korean threats and said she hoped Pyongyang could return to talks on abandoning its nuclear programs.
Speaking at a news conference, Clinton also said that North Korea, which conducted its second nuclear test on Monday, was behaving in a provocative and belligerent manner toward its neighbors and there were consequences to such behavior.
North Korea threatened military action Wednesday against US and South Korean warships plying the waters near the Koreas' disputed maritime border, raising the specter of a naval clash just days after the regime's underground nuclear test.
Pyongyang, reacting angrily to Seoul's decision to join an international program to intercept ships suspected of aiding nuclear proliferation, called the move tantamount to a declaration of war.
"Now that the South Korean puppets were so ridiculous as to join in the said racket and dare declare a war against compatriots," North Korea is "compelled to take a decisive measure," the Committee for the Peaceful Reunification of Korea said in a statement carried by state media.
The North Korean army called it a violation of the armistice the two Koreas signed in 1953 to end their three-year war, and said it would no longer honor the treaty.
Reuters and AP contributed to the story