North Korea walked away from talks on its nuclear programme last year
North Korean leader Kim Jong-il has told China he is committed to ridding the Korean peninsula of nuclear weapons, Chinese state media has said.
His comments came during a visit to the North by senior Beijing envoy Wang Jiarui and prior to the arrival of senior UN envoy, Lynn Pascoe.
The diplomats are thought to be trying to restart multi-nation talks with the North on ending its nuclear programme.
Pyongyang pulled out of talks after the UN condemned its testing of missiles.
The BBC's John Sudworth in Seoul says Mr Kim's statement is broad aspiration, containing no details about how and when the transformation would occur.
But coming amid the flurry of diplomatic activity, it has led to speculation that North Korea may be preparing to return to the talks, our correspondent adds.
Xinhua said Mr Kim had reiterated North Korea's "persistent stance to realise the denuclearisation of the Korean Peninsula" in the talks with Mr Wang, head of the Communist Party's international department.
"The sincerity of relevant parties to resume the six-party talks is very important," Xinhua quoted Mr Kim as saying.
He said North Korea was willing to strengthen communication and coordination with China.
Mr Wang delivered to Mr Kim a letter from Chinese President Hu Jintao, in which he said Beijing was ready to work with North Korea to maintain peace and stability on the peninsula and invited Mr Kim to visit China, Xinhua added.
Mr Wang was accompanied back to Beijing by the North's nuclear envoy, Kim Kye-gwan, South Korea's Yonhap news agency reported.
Citing unidentified diplomatic sources in Beijing, Yonhap said the North Korean envoy's trip was believed to be aimed at discussing the six-party talks.
The visit by Mr Pascoe, the top advisor to UN Secretary General Ban K-moon, marks the most senior UN trip to the North since 2004.
He will urge North Korea to rejoin the nuclear talks and discuss the country's relationship with the world body, the Associated Press news agency quoted a UN official in New York as saying.
Talks involving North Korea have a tortured history of stops and starts - formerly held under the six-party format which includes the two Koreas, the US, Russia, China and Japan.
Last weekend, the North released an American missionary detained since Christmas for illegal entry, and on Monday officials from the two Koreas met in a North Korean border town to discuss restarting joint tourist trips suspended in 2008.
North Korea has made clear it wants sanctions lifted and a peace treaty to formally end the 1950-1953 Korean War before returning to the disarmament talks.
Washington has responded that Pyongyang must come back to the talks first before any talk about political and economic concessions.