Flags of China and North Korea are seen outside the closed Ryugyong Korean Restaurant in Ningbo, Zhejiang province, China, April 12, 2016. Reuters/Joseph Campbell Beijing will work with Pyongyang to safeguard, consolidate and ­develop their friendship, ­President Xi Jinping told a visiting North Korean envoy, ­despite the deteriorated ties ­between the two neighbours.

China also hoped all parties ­involved in the North Korean ­nuclear issue would exercise ­restraint to better facilitate ­communication, Xinhua quoted Xi as telling Ri Su-yong, Pyongyang’s former foreign minister and serving vice-chairman of the Workers’ Party of Korea, who is visiting Beijing.

Analysts said the meeting was a significant development in the improvement of relations between the two nations.“The meeting sent out a positive signal that both countries are actively seeking to improve bilateral relations, said Yu Shaohua, director of the Department for Asia-Pacific ­Security and Cooperation at the China Institute of International Studies.

Ties have suffered since the North carried out a fourth nuclear test in January and followed it up with a long-range rocket launch in February. In response, China joined the rest of the United ­Nations Security Council in backing tough sanctions. Yu said the two countries’ differences over the North’s nuclear programme would take time to resolve.

Xi has never met the North’s leader Kim Jong-un, but early this month, Xi sent a message to ­congratulate him on his election as ruling party chairman at a congress last month. Beijing did not send an envoy to the political gathering, but the Pyongyang ­delegation was due to brief Chinese officials on the meeting.

Xi said the visit suggested Kim attached great importance to ties between the parties, as well as the two nations. Yu said it was a tradition for China and North Korea to update each other after a major party congress. “Although it is a bit late … both sides have placed a high emphasis on developing bilateral relations,” she said.

Chinese Vice President Xi Jinping delivers a speech during a joint media briefing with Romania's President Traian Basescu (unseen) at Cotroceni presidential palace in Bucharest October 19, 2009. REUTERS/Bogdan Cristel

But Ri also told Song Tao , the Chinese Communist Party’s International Department chief, the North had no plans to ­abandon its nuclear programme, saying its guiding principle had been “simultaneously pushing forward economic construction and the building of nuclear force”, according to the official Korean Central News Agency.

Daniel Russel, the top American diplomat for East Asia, said on Tuesday that high-level talks between the US and China in Beijing next week would provide an ­opportunity to “game out” how to ­pressure the North to agree to negotiations on the denuclearisation of the Korean peninsula.

“That’s not unconditional surrender. That’s a reasonable and consistent objective of ours. We have a vastly improved chance of getting that with China’s full ­cooperation,” Russel said.

“The outcome that we’re looking for is North Korean agreement to negotiate the denuclearisation of the Korean peninsula.”

China is the only major ally of the reclusive North and is estimated to provide up to 90 per cent of its energy imports, 80 per cent of its consumer goods and 45 per cent of its food, according to the US-based Council on Foreign Relations.

Although Beijing was angered by Pyongyang’s nuclear and missile tests, the Chinese leadership has been reluctant to take tougher action – for example by shutting their shared border – out of concern the country could collapse or fall into civil strife.

Additional reporting by Reuters and Associated Press.