North Korea escalated its vitriol against South Korea and the United States on Wednesday with warnings of a \u201cpowerful military strike\u201d\u009d if any North Korean ships were stopped or searched as part of an American-led operation to intercept vessels suspected of carrying unconventional weapons.<\/p>\n
South Korea agreed to join the operation after North Korea tested a nuclear device on Monday, its second nuclear test in three years. The North had earlier warned the South not to participate in the operation, known as the Proliferation Security Initiative.<\/p>\n
\u201cWe consider this a declaration of war against us,\u201d\u009d North Korea said in a statement carried by its official news agency, KCNA. \u201cAny hostile act against our peaceful vessels, including search and seizure, will be considered an unpardonable infringement on our sovereignty, and we will immediately respond with a powerful military strike.\u201d\u009d<\/p>\n