Mr. Kim’s friendly welcome also contrasted with the reception that Mr. Song received the last time he visited North Korea, as a special envoy of Mr. Xi in November. At that time, Mr. Kim refused to meet him and launched an intercontinental ballistic missile several days later.
This time, Beijing sent Mr. Song and an art troupe to Pyongyang, the North Korean capital, to attend an international art festival.
On Saturday, Mr. Kim “expressed satisfaction with improving ties between the two parties and nations,” the North Korean news agency said. “He voiced a need to elevate the traditional friendship to a new level of development meeting new demands of the times.”
Ties between China and North Korea had become strained in recent years, as Mr. Kim conducted a series of nuclear and missile tests and Beijing voted for increasingly harsh United Nations sanctions designed to squeeze the North to stop. The sanctions banned all major North Korean exports, such as coal, iron ore, textiles and seafood.
Those sanctions have hit the isolated North hard, as China accounts for more than 90 percent of North Korea’s external trade.
Until recently, Mr. Kim had refused to enter any talks on ending his nuclear weapons program. Instead, he accelerated his missile and nuclear tests after taking power in 2011, and declared in this year’s New Year’s Day speech that the North had achieved its goal of developing a nuclear deterrent.
Since then, he has suddenly shifted toward dialogue. He agreed to meet with President Moon on the inter-Korean border on April 27. President Trump has also accepted Mr. Kim’s invitation to a summit, agreeing to meet him in May or early June. Mr. Kim said he was willing to discuss denuclearizing if certain conditions, such as security guarantees for his regime, are met.