SEOUL/UNITED NATIONS - North Korea threatened the United States on Thursday with a preemptive nuclear strike, raising the level of rhetoric just before the UN Security Council approved new sanctions against the reclusive country.
US Ambassador to the United Nations Susan Rice said North Korea's threats would achieve nothing and would only further isolate the country.
China's UN Ambassador Li Baodong said Beijing wanted to see "full implementation" of the new UN Security Council resolution that tightens financial restrictions on Pyongyang and cracks down on its attempts to ship and receive banned cargo.
North Korea has accused the United States of using military drills in South Korea as a launch pad for a nuclear war and has scrapped the armistice with Washington that ended hostilities in the 1950-53 Korean War.
North Korea, which has one major ally, neighboring China, threatens the United States and its "puppet," South Korea, on an almost daily basis.
"Since the United States is about to ignite a nuclear war, we will be exercising our right to preemptive nuclear attack against the headquarters of the aggressor in order to protect our supreme interest," the North's foreign ministry spokesman said in a statement carried by the official KCNA news agency.
North Korea conducted a third nuclear test on Feb. 12, in defiance of UN resolutions, and declared it had achieved progress in securing a functioning atomic arsenal. It is widely believed that the North does not have the capacity for a nuclear strike against the United States mainland.
With tensions high on the Korean peninsula, the UN Security Council voted to expand its sanctions on North Korea. The new sanctions were agreed after three weeks of negotiations between the United States and China, which has a history of resisting tough measures against its ally.
The resolution specifies some luxury items North Korea's elite is not allowed to import, such as yachts, racing cars, luxury automobiles and certain types of jewelry. This is intended to close a loophole that had allowed countries to decide for themselves what constitutes a luxury good.
"These sanctions will bite and bite hard," said Rice.
The export of luxury goods to North Korea has been prohibited since 2006, though diplomats and analysts said the enforcement of UN sanctions has been uneven.
UN Secretary-General Ban Ki-moon, a former South Korean foreign minister, welcomed the council's move, saying in a statement that the resolution "sent an unequivocal message to (North Korea) that the international community will not tolerate its pursuit of nuclear weapons."
North Korea's threats were the latest in an escalation in a war of words by both sides across the armed Korean border this week.
The North's unnamed foreign ministry spokesman said it would be entitled to take military action as of March 11 when US-South Korea military drills move into a full-scale phase as it had declared the truce invalid.
"North Korea will achieve nothing by continued threats and provocations. These will only further isolate the country and its people and undermine international efforts to promote peace and stability in northeast Asia," Rice told reporters.
US President Barack Obama's administration said it had reassured South Korea and Japan "at the highest levels" of its commitment to deterrence, through the US nuclear umbrella and missile defense, in the face of the new threats from North Korea.
Glyn Davies, the State Department's point man for North Korea policy, also said in testimony prepared for a Senate hearing that Washington will not accept North Korea as a nuclear state.
North Korea, which held a mass military rally in Pyongyang on Thursday in support of its recent threats, has protested against the UN censures of its rocket launches. It says they are part of a peaceful space program and that the criticism is an exercise of double standards by the United States.
The North's shrill rhetoric, however, rarely goes beyond just that. Its last armed aggression against the South in 2010 came unannounced, bombing a South Korean island killing two civilians. It was widely accused of sinking a South Korean navy ship earlier in the year, killing 46 sailors.
North Korea was conducting a series of military drills and getting ready for state-wide war practice of an unusual scale, South Korea's defense ministry said earlier.
South Korea and the United States, which are conducting annual military drills until the end of April, are watching the North's activities for signs they might turn from an exercise to an actual attack, a South Korean official said.
"It hasn't been frequent that the North conducted military exercises at the state level," said South Korea's defense ministry spokesman, Kim Min-seok. "The North is currently conducting various drills on land, at sea and aerially.
"We are watching the North's activities and stepping up readiness under the assumption that these drills can lead to provocation at any time."
Kim declined to confirm news reports that the North has imposed no-fly zones off its coasts in a possible move to fire missiles, but he said any flight ban limited to near the coast would not be for weapons with meaningful ranges.
A North Korean general said on Tuesday that Pyongyang was scrapping the armistice. But the two sides remain technically at war as the civil war did not end with a treaty.
South Korea's military said in a rare warning on Wednesday that it would strike back at the North and target its leadership if Pyongyang launched an attack.