UNITED NATIONS, (AFP) - New nuclear sanctions against North Korea agreed by the UN Security Council on Thursday will "bite hard," the US ambassador to the United Nations, Susan Rice, said.

"Taken together, these sanctions will bite and bite hard. They increase North Korea's isolation and raise the cost to North Korea's leaders of defying the international community," Ms Rice told reporters after the unanimous vote by the council.

The 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 U.N.'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.

The new sanctions are aimed at making it more difficult for North Korea to finance and obtain material for its weapons programs.