A special envoy from North Korean leader Kim Jong-Un told one of China's top officials Thursday that Pyongyang wants peace and is willing to pursue dialogue with key countries, state media reported.

Envoy Choe Ryong-Hae met Liu Yunshan, a member of the Chinese Communist Party's highest ranking body the Politburo Standing Committee, state television reported on its evening newscast.

China is the North's sole major ally and key economic benefactor. But relations have taken a downturn in recent months in the face of escalating tensions on the Korean peninsula after Pyongyang's nuclear and missile tests, which saw international sanctions tightened.

The North -- angered by the sanctions and US-South Korean exercises -- threatened nuclear attacks on Seoul and Washington, sending military tensions sharply higher.

The report quoted Choe as telling Liu he was sent by Kim to improve, consolidate and further develop relations and that the North was willing to work with China.

Choe also praised China's efforts for peace and stability on the Korean peninsula. He said the North was willing to accept Beijing's proposals to develop dialogue with other parties.

It was not immediately clear if he was referring to long-stalled efforts -- the so-called six-party talks -- by China, Japan, the United States, Russia and South Korea to persuade the North to abandon its nuclear programme in exchange for aid and security guarantees.

Choe said his country "hopes to concentrate its energy on developing its economy and improving people's livelihood and is ready to create a peaceful external environment for this", China's state news agency Xinhua reported.

Choe, a vice marshal and director of the Korean People's Army's General Political Bureau, is said to be a close confidant of Kim, who has led North Korea for more than a year.

He is believed to be the highest-ranking North Korean to visit China since Kim's late father and predecessor Kim Jong-Il in August 2011. The elder Kim died in December 2011.

Liu told Choe that China hopes all relevant parties will work for denuclearisation of the Korean peninsula, solve problems through dialogue and achieve an early restart of the six-party talks.

The report showed footage of the talks in Beijing's elaborate Great Hall of the People, with Choe dressed in military uniform. Other officials from both sides also attended.

The Politburo Standing Committee has only seven members and is led by President Xi Jinping.

The meeting with Liu was preceded Wednesday by one with Wang Jiarui, head of the ruling party's International Department, which Beijing said was to "exchange views" on "issues of common interest".

Earlier Thursday Chinese foreign ministry spokesman Hong Lei gave no details of Choe's trip.

It remained unclear if the North korean envoy would meet Xi during his visit.

Before news of the meeting with Liu, state media had quoted Chinese analysts as saying that the rank of the officials Choe was allowed to meet would be a key in determining the visit's success.

Choe's trip comes ahead of a flurry of high-level diplomacy involving China and other key players.

President Xi will meet US President Barack Obama on June 7-8 in the United States for their first summit.

Hong confirmed that South Korea's new president will pay a state visit to China in late June.

"We believe that President Park Geun-Hye's state visit to China will bring China-Republic of Korea relations to a new and higher level," he said, using the South's official name.