The UN Security Council has voted unanimously for tough new sanctions to punish North Korea for its latest nuclear test, a move that sparked a furious Pyongyang to threaten a nuclear strike against the United States.

The vote Thursday by the UN's most powerful body on a resolution drafted by North Korea's closest ally, China, and the United States sends a powerful message to North Korea that the international community condemns its ballistic missile and nuclear tests — and its repeated violation of Security Council resolutions.

Immediately before the vote, an unidentified spokesman for Pyongyang's Foreign Ministry said early Thursday the North will exercise its right for "a preemptive nuclear attack to destroy the strongholds of the aggressors" because Washington is pushing to start a nuclear war against the North.

The White House responded by saying the U.S. is prepared to defend itself against a North Korean attack.

"I can tell you that the United States is fully capable of defending against any North Korean ballistic missile attack," said White House spokesman Jay Carney.

Sanctions target ruling elite

Although North Korea boasts of nuclear bombs and pre-emptive strikes, it is not thought to have mastered the ability to produce a warhead small enough to put on a missile capable of reaching the U.S. It is believed to have enough nuclear fuel, however, for several crude nuclear devices.

The new sanctions are aimed at reining in North Korea's nuclear and missile programs by making it more difficult for Pyongyang to finance and obtain material for these programs, tracking illegal diplomatic activity and intensifying inspections of cargo to and from the country. In a measure targeted at the reclusive nation's ruling elite, the resolution bans all nations from exporting expensive jewelry, yachts, luxury automobiles and racing cars to the North.

After the 15-0 vote, U.S. Ambassador Susan Rice told reporters that "taken together, these sanctions will bite and bite hard." Responding to Pyongyang's nuclear strike threat, she said, "North Korea will achieve nothing by continued threats and provocation."

She urged North Korea's leaders to heed President Barack Obama's call to follow the path of peace. If it doesn't, she said, the Security Council is committed in the resolution to take further measures.

The top U.S. envoy on North Korea, Glyn Davies, cautioned Pyongyang not to miscalculate, saying the U.S. will take necessary steps to defend itself and its allies, including South Korea, where it bases over 30,000 U.S. military personnel.

The U.S. also provides what it calls a "nuclear umbrella" security guarantee to both South Korea and Japan, neighbours of North Korea which do not have nuclear weapons and missile defence capabilities.

"We take all North Korean threats seriously enough to ensure that we have the correct defence posture to deal with any contingencies that might arise," Davies told reporters after testifying to a Senate foreign relations panel.

China's UN Ambassador Li Bao Dong said the top priority now is to "bring down the heat" and focus on diplomacy and restarting the six-party talks aimed at denuclearizing the Korean peninsula.

North Korea 'ready' to strike U.S

In North Korea, Army Gen. Kang Pyo Yong told a crowd of tens of thousands that North Korea is ready to fire long-range nuclear-armed missiles at Washington.

"Intercontinental ballistic missiles and various other missiles, which have already set their striking targets, are now armed with lighter, smaller and diversified nuclear warheads and are placed on a standby status," Kang said. "When we shell (the missiles), Washington, which is the stronghold of evils... will be engulfed in a sea of fire."

Inside North Korea

North Korea allowed photojournalists restricted access to the country as it prepared to celebrate the 100th birth anniversary of its late leader Kim Il-sung in April, 2012.

The statement by the North Korean Foreign Ministry spokesman was carried by the North's official Korean Central News Agency.

It accused the U.S. of leading efforts to slap sanctions on North Korea. The statement said the new sanctions would only advance the timing for North Korea to fulfil previous vows to take "powerful second and third countermeasures" against its enemies. It hasn't elaborated on those measures.

The statement said North Korea "strongly warns the UN Security Council not to make another big blunder like the one in the past when it earned the inveterate grudge of the Korean nation by acting as a war servant for the U.S. in 1950."

North Korea demanded the Security Council immediately dismantle the American-led UN Command that is based in Seoul and move to end the state of war that exists on the Korean Peninsula, which continues six decades after fighting stopped because an armistice, not a peace treaty, ended the war.

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Soldiers of Kim Il Sung Military University perform military training on Wednesday, in Pyongyang. (Kim Kwang Hyon/Associated Press)

In anticipation of the resolution's adoption, North Korea earlier in the week threatened to cancel the 1953 cease-fire that ended the Korean War.

North Korean threats have become more common as tensions have escalated following a rocket launch by Pyongyang in December and its third nuclear test on Feb. 12. Both acts defied three Security Council resolutions that bar North Korea from testing or using nuclear or ballistic missile technology and from importing or exporting material for these programs.

New individuals, groups added to sanctions list

The UN resolution identifies three individuals, one corporation and one organization that will be added to the UN sanctions list. The targets include top officials at a company that is the country's primary arms dealer and main exporter of ballistic missile-related equipment, and a national organization responsible for research and development of missiles and probably nuclear weapons.

The success of a new round of sanctions could depend on enforcement by China, where most of the companies and banks that North Korea is believed to work with are based.

To get around financial sanctions, North Koreans have been carrying around large suitcases filled with cash to move illicit funds. The resolution expresses concern that these bulk cash transfers may be used to evade sanctions. It clarifies that the freeze on financial transactions and services that could violate sanctions applies to all cash transfers as well as the cash couriers.

The resolution also bans all countries from providing public financial support for trade deals, such as granting export credits, guarantees or insurance, if the assistance could contribute to the North's nuclear or missile programs