US Secretary of State Hillary Clinton has urged North Korea to return to its obligations to rid the Korean peninsula of nuclear weapons.

美国国务卿希拉里克林顿督促朝鲜实现自己的义务，解决半岛核问题。

The resumption of reprocessing follows a missile test

Earlier, North Korea announced it had started re-processing spent fuel rods（燃料棒） at the Yongbyon nuclear plant.

Mrs Clinton said she hoped the US and its partners would be able to resume discussions with Pyongyang.

Pyongyang pulled out of six-party talks last week, in response to world condemnation¹（非难） of a recent missile test.

The reprocessing is a possible move towards producing weapons-grade plutonium（钚）.

The UN Security Council imposed sanctions（制裁） on three North Korean companies in response to the missile launch.

Pyongyang said it would ignore the sanctions, describing them as "a wanton（荒唐的，嬉戏的） violation² of the UN charter".

Satellite view of nuclear site

'Unacceptable'

North Korea agreed in 2005 to abandon all nuclear weapons and existing nuclear programmes and return, at an early date, to the Treaty on Non-Proliferation（增殖，分芽繁殖） of Nuclear Weapons and to UN safeguards.

The US has been involved in six-party talks including both Koreas, China, Japan and Russia.

Speaking in Baghdad, Mrs Clinton welcomed the UN Security Council's "strong statement" on the missile test.

"We hope that we'll be able to resume discussions with North Korea that will lead to their assuming responsibility for denuclearising the peninsula," she said.

Megan Mattson, a US state department spokeswoman, said separately: "We will not accept North Korea as a nuclear-weapons state."

North Korea's state news agency announced the resumption（恢复） of spent fuel rod re-processing.

The re-processing would "contribute to bolstering³（支持，支撑） the nuclear deterrence⁴（妨碍物） for self-defence", a North Korean official told the agency.

The BBC's John Sudworth in Seoul says the move confirms that, for now at least, North Korea is serious about turning its back on the six-party talks.

North Korea had partially⁵ dismantled⁶（拆除，分解） its nuclear reactor⁷ - the source of material for a 2006 atomic test - but is thought to possess enough reprocessed plutonium for between six and eight nuclear weapons.

Therefore, in the immediate⁸ term, Pyongyang's announcement does not significantly alter the strategic balance, our correspondent adds.