Chinese President Xi Jinping says he and North Korean leader Kim Jong-un have reached an "important consensus" and agreed to safeguard regional and global peace.
Xi issued a message of thanks following his visit to Pyongyang, North Korean state media KCNA said on Wednesday.
Xi said the two sides had "exchanged in-depth views on issues of common concern and reached a series of important joint consensus", reflecting their determination to further deepen ties.
Xi said he was willing to work with Kim "based on fundamental and long-term interests" to "steadily safeguard, consolidate and develop" bilateral ties and contribute more to regional and global peace and development.
He also said the visit had been "successfully concluded" and that relations had entered "a new historical stage", while expressing hope to meet Kim again.
Xi visited Pyongyang from Monday to Tuesday in his first trip to North Korea in seven years.
Xi said the visit had established a deeper, more comprehensive understanding yielding a clearer path for development of ties, China's official Xinhua news agency said.
The two leaders agreed to expand co-operation across politics, the economy, trade and culture, while pledging closer strategic communication between their governments, according to both countries' state media.
"Practical co-operation is an important driving force behind the development of China-DPRK relations," Xinhua said, noting also sectors such as agriculture, technology and construction.
Both nations should also capitalise on a full reopening of border crossings and the resumption of civil aviation flights and international passenger trains, Chinese official media said.