North Korean leader Kim Jong-il is committed to ending the North's nuclear programme, Chinese state media says.

中国新华社报道，朝鲜领导人金正日愿意停止核试验。

It was Kim Jong-il's fifth to China since succeeding his father in 1994

Mr Kim's secretive visit to Beijing was only confirmed once it was finished.

He told Chinese President Hu Jintao he would work with China "to create favourable¹ conditions" for talks, state news agency Xinhua reported.

Six-party negotiations² to dismantle³ the North's nuclear capability⁴ are hosted by China and involve the two Koreas, the US, Japan and Russia.

North Korea quit the talks in April 2009, after the UN imposed sanctions（制裁，处罚） for a missile test.

Mr Kim - who arrived in China on Monday and has now returned to Pyongyang - was accorded（一致，符合） the rare distinction of meeting all of China's top leaders during his visit.

"The DPRK (North Korea) is willing to work with you to create favourable conditions for a resumption（恢复） of the six-party talks," Xinhua quoted Mr Kim as telling President Hu.

The BBC's Michael Bristow in Beijing says a close examination of Mr Kim's comments suggests the aim of persuading Pyongyang to give up its nuclear ambitions remains⁵ a distant goal.

The North Korean leader did not wholeheartedly（全心全意地） commit to returning to the six-nation talks, our correspondent notes.

Premier⁶ Wen Jiabao was quoted as telling Mr Kim in a separate meeting: "China will, as always, support the DPRK's economic development and improving people's livelihood⁷（生计，生活） ."

Both sides said they would strengthen economic ties and look for new investment projects.

State TV footage showed Mr Kim, who is 68 years old, looking frail⁸（虚弱的，脆弱的） and thin.

The North Korean leader is believed to have suffered a stroke in 2008.

Speculation⁹ over his health has fuelled uncertainty¹⁰ about who will succeed him and the impact on Pyongyang's nuclear capability.

The North's Korean Central News agency said Mr Kim's "unofficial" visit ended on Friday.

"The leader of the DPRK received a sincere and warm welcome from Chinese people wherever he went in China," it reported. "Kim Jong-il expressed satisfaction over the result of his visit."

This week's visit was Mr Kim's fifth to China since succeeding his father as ruler in 1994, with the last in 2006.