The U.N. Security Council took direct aim at North Korea’s leadership Thursday with new sanctions targeting cash transfers and luxury items, punishing the reclusive regime for its latest nuclear test while evoking a fresh torrent of threats from the North Korean capital.

The sanctions, drafted by the United States and China and approved unanimously, were adopted against a backdrop of apocalyptic rhetoric from Pyongyang, including a threat to launch a preemptive nuclear strike against foreign “aggressors,” a term traditionally interpreted to include the United States.

The Obama administration dismissed the threat and warned North Korea of further isolation and economic pain if it conducts more nuclear tests.

“We are fully capable of defending the United States,” State Department spokeswoman Victoria Nuland told reporters in Washington shortly after the U.N. vote.

Hours after the sanctions were approved, North Korea also said it would nullify a nonaggression agreement with South Korea and close a liaison channel along the demilitarized border that divides the two countries.

The sanctions approved by the 15-member Security Council were among the most comprehensive in recent years, as the world body acted with unanimity to denounce North Korea’s third nuclear test since 2006.

The U.N. resolution imposed new restrictions on North Korean shipping firms and financial institutions and sought to block certain kinds of cash transfers frequently used by North Korean officials to obtain weapons-sensitive technology or to circumvent existing sanction law. A provision that directly targeted the North’s ruling elite also tightened restrictions on overseas travel and on the importation of such luxury items as yachts, jewelry and racing cars.

The council warned of “further significant measures” if the North carried out another nuclear or ballistic missile test, a threat echoed by U.S. officials and diplomats. “Taken together, these sanctions will bite, and bite hard,” Susan E. Rice, U.S. ambassador to the United Nations, said after the vote.

China’s prominent role in drafting the measures highlighted the growing isolation of the hermetic Stalinist state, long regarded as a close ally of Beijing. China’s U.N. envoy, Li Baodong, described the vote as one step in a “hard, tedious” journey to achieve the denuclearization of the Korean Peninsula. He said his government hopes the international community will now pursue talks with Pyongyang.

“The adoption of the resolution . . . is not for the sake of sanctions,” Li said after the vote. “The top priority now is to defuse the tension, bring down the heat, focus on [the] diplomatic track.”

There were no conciliatory signs from Pyongyang. Instead, in the hours before the vote, the North increased its bluster, issuing taunts and threats that were shrill even by North Korean standards.

A Foreign Ministry statement published by Pyongyang’s news agency decried the new sanctions as part of a U.S.-led “war of aggression,” vowing that the North would respond with a display of “the might . . . it built up decades after decades, and put an end to the evil cycle of tension.” The statement further warned that Pyongyang would exercise its right for “a preemptive nuclear attack to destroy the strongholds of the aggressors.”

White House spokesman Jay Carney dismissed the threat, citing improved U.S. missile-defense capabilities against the “limited ballistic missile threats” that might emanate from North Korea in the coming years.

“Let us be clear: We are fully capable of dealing with that threat,” Carney said.

On Capitol Hill, Glyn T. Davies, the State Department’s special representative for North Korean policy, said Pyongyang’s recent nuclear test was the latest in a series of provocations that demanded a firm global response.

“North Korea’s [weapons of mass destruction], ballistic missile, conventional arms and proliferation activities constitute a serious and unacceptable threat to U.S. national security,” Davies said in testimony before the Senate Foreign Relations Committee.

“The . . . leadership in Pyongyang faces sharp choices,” Davies said, “and we are working to further sharpen those choices.”

Warrick reported from Washington. Chico Harlan in Seoul contributed to this report.