Vice-President Li Yuanchao reaffirmed China's commitment to ridding the Korean peninsula of nuclear weapons - and called for new six-party talks to achieve that goal - in a meeting with North Korean leader Kim Jong-un.
Li met Kim while in Pyongyang to mark the 60th anniversary of the signing of the Korean armistice agreement. China helped Pyongyang fight to stalemate against UN forces led by the US in the 1950-53 conflict.
"As a close neighbour of the Korean peninsula, China persists in the realisation of its denuclearisation and the maintenance of its peace and stability," Li told Kim, according to Xinhua. "China insists that problems should be solved by dialogue and negotiation."
Li - the highest-ranking Chinese official to visit North Korea since Kim succeeded his father in late 2011 - verbally delivered a message from President Xi Jinping to the young North Korean leader.
Li reiterated Beijing's stance that it was willing "to work with all concerned parties to promote the six-party talks" and "is committed to pushing for the process of denuclearisation".
The six-party talks, involving China, Japan, Russia, the United States and the two Koreas, began in 2003 and stalled in 2008 when North Korea walked away from any proposed deal. The talks were hosted by China.
In response, Kim told Li that the North "supports China's efforts to resume the six-party talks". Kim said the country was "willing to work with all other parties to ensure peace and security in the Korean peninsula".
Ties between the communist allies were tested earlier this year by North Korea's nuclear test and rocket launches. The provocation caused Beijing to join the US in backing UN sanctions against the North.
"The visit is both symbolic and substantial in terms of improving relations," said Professor Wang Xinsheng , a Peking University historian who specialises in Northeast Asia.
Wang said economic difficulties were likely to drive Pyongyang's efforts to reaffirm ties with China and its commitment to eventually rejoin the six-nation talks.
He said he would expect the high-level meeting with Li to produce "some substantial result".
Beijing has long played a crucial role in maintaining the Kim family's status.
Kim said Pyongyang had a "treasured traditional friendship with China" and "was willing to strengthen communication with the Chinese side to increase co-operation and promote the development in bilateral relations between the two nations", Xinhua reported.