SEOUL, South Korea - North Korea's military is vowing to cancel the 1953 cease-fire that ended the Korean War, straining already frayed ties between Washington and Pyongyang as the United Nations moves to impose punishing sanctions over the North's recent nuclear test.

Without elaborating, the Korean People's Army Supreme Command boasted of having "lighter and smaller nukes" and warned late Tuesday of "surgical strikes" meant to unify the divided Korean Peninsula.

The statement cited ongoing U.S.-South Korean joint military drills that Pyongyang propaganda considers invasion preparation, and a U.S.-led push to secure a U.N. Security Council resolution calling for sanctions in response to North Korea's Feb. 12 nuclear test. A U.S.-China draft resolution is expected to be circulated at the U.N. this week.

Heated military rhetoric is common from North Korea when tensions rise on the Korean Peninsula and during U.S.-South Korean war drills, and Pyongyang has previously threatened to tear up the cease-fire. But this latest statement is unusually specific in its details and is seen as noteworthy by officials in Seoul because a senior North Korean military official issued the threats on state TV.

The North's statement threatens to block a communications line between North Korea and the United States at the border village separating the two Koreas, and to nullify the 60-year-old Korean War armistice agreement on March 11, when two weeks of U.S.-South Korean military drills will draw 10,000 South Korean and 3,500 U.S. forces. Another round of drills between the allies began earlier this month.

Pyongyang's recent nuclear test and rocket launches, and the subsequent call for U.N. punishment, have increased already high animosity between the North and Washington and Seoul.

The United States and others worry that North Korea's third nuclear test takes it a big step closer toward its goal of having nuclear-armed missiles that can reach America, and condemn its nuclear and missile efforts as threats to regional security and a drain on the resources that could go to North Korea's largely destitute people.

North Korea says its nuclear program is a response to U.S. hostility that dates to the 1950-53 Korean War, which ended with an armistice, not a peace treaty, leaving the Korean Peninsula still technically in a state of war.

Even amid the tension, however, North Korea has recently welcomed high-profile American visitors, including former basketball star Dennis Rodman, known for his piercings and tattoos as much as his Hall of Fame career with the Detroit Pistons and Chicago Bulls.

Rodman met the North Korean leader, Kim Jong Un, called him an "awesome guy" and said Kim wanted President Barack Obama to call him. The trip was criticized for giving the authoritarian leader a propaganda boost, but Rodman suggested "basketball diplomacy" could warm relations. Google's executive chairman, Eric Schmidt, made a four-day trip in January, but did not meet Kim.

North Korean propaganda regularly cites decades-old, Cold War-era American threats as the reason for its nuclear efforts and holds that the North remains at risk of an unprovoked nuclear attack. Washington and others say brinksmanship is the North's true motive for the nuclear push.

The North's statement called U.S.-South Korean military drills a "dangerous nuclear war targeted at us."

"We aim to launch surgical strikes at any time and any target without being bounded by the armistice accord and advance our long-cherished wish for national unification," the statement said.

The U.S.-China draft resolution at the U.N. would impose some of the strongest sanctions ever ordered by the United Nations, diplomats said. It reflects the U.N. Security Council's growing anger over the country's defiance of three previous rounds of sanctions aimed at halting all nuclear and missile tests.

The draft resolution would make it significantly harder for North Korea to move around the funds it needs to carry out its illicit programs.

It would also strengthen existing sanctions that bar North Korea from testing or using nuclear or ballistic missile technology and from importing or exporting material for these programs. It would strengthen the inspection of suspect cargo bound to and from the country.

Many analysts believe that the success of this new round of sanctions depends largely on how well China enforces them. Most of the companies and banks that North Korea is believed to work with are based in China.

U.S. Secretary of State John Kerry said President Barack Obama and the American people want to see North Korean leader Kim Jung Un engage in peace talks.

Kerry also stressed that the United States will continue "to do what is necessary to defend our nation and the region together with our allies."

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Associated Press writers Youkyung Lee, Hyung-jin Kim and Sam Kim in Seoul and Edith M. Lederer at the United Nations contributed to this report.