North Korea has pledged to strengthen its nuclear weapons programme, after the UN Security Council voted to expand existing sanctions against Pyongyang.

North Korea said on Wednesday it would hold no more talks on the denuclearisation of the Korean peninsula and would boost its military and nuclear capabilities.

"We will take measures to boost and strengthen our defencive military power including nuclear deterrence," its foreign
ministry said in a statement carried by state news agency KCNA.

Hours earlier, the Security Council voted unanimously to condemn North Korea's December rocket launch.

The launch is considered by the West as part of a covert programme to develop ballistic missiles that can carry warheads.

The council reiterated its previous demand that North Korea abandon its nuclear weapons programme in a "complete, verifiable and irreversible manner" and cease launches.

The secretive state, already under tough UN sanctions for nuclear tests in 2006 and 2009, said the launch was intended to put a satellite in space.

'US-China deal'

North Korea's space agency and new individuals were added to the UN sanctions list for an assets freeze and travel ban. The resolution approved by the 15-nation council was the result of a deal between the US and China, envoys said on condition of anonymity.

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China and the US held weeks of top-level negotiations over the international response before the resolution was submitted for a vote.

Al Jazeera's James Bays, reporting from the UN headquarters, said: "In the past there was opposition from China to any fresh action against North Korea.

"I think what changed things was the rocket launch in December, described as a "defiant step" by the international community."

Tough measures were sought by the US against North Korea's government, while China has sought to shield its trade ally against sanctions.

Even though the resolution does not impose new sanctions on Pyongyang, diplomats said China's support was a significant diplomatic blow to Pyongyang.

Six-party talks aimed at halting North Korea's nuclear programme have involved North Korea, the US, China, Japan, Russia and South Korea. They have been held intermittently since 2003, but stalled since 2008.

South Korea says the North is technically ready for a third nuclear test, and satellite images show it is actively working on its nuclear site.

Source: Al Jazeera and agencies