President Xi Jinping has replied to North Korean leader Kim Jong-un’s message of congratulations after the Communist Party congress, with the Chinese leader saying he is hoping to improve ties between the two nations, according to North Korean state media. The message comes as US President Donald Trump is about to start his first trip to Asia while in office, with North Korea’s nuclear weapons programme likely to be high on his agenda. Details of Xi’s message were reported by North Korea’s official news agency, but his remarks were not carried by Chinese state media. “I wish that under the new situation the Chinese side will make efforts with the DPRK to promote relations between the two parties … for stable development and thus make a positive contribution to providing the peoples of the two countries with greater happiness and to defend regional peace and stability and common prosperity,” Xi was quoted as saying by the Korean Central News Agency. Will Donald Trump stay on script or prompt ‘white knuckles’ on his Asian trip? Kim wished Xi great success heading China’s government after the Communist Party congress concluded last month, a rare personal message from the North Korean leader to another head of state. Ties between the two countries and traditional allies are strained amid Pyongyang’s development of nuclear weapons, with China backing UN sanctions to rein in North Korea’s nuclear programme. Analysts say Trump is likely to call on China to take tougher against North Korea during his trip to Asia, which begins on Friday. Trump has previously threatened to use military force to strike against Pyongyang. Xi has yet to visit North Korea since taking office and Kim has also not visited China since becoming leader in 2011. Guo Yezhou, vice-minister of the Chinese Communist Party’s international department, said last month that communication channels between China and North Korea were open, but added it would depend on “mutual willingness” whether the two leaders would meet. China, the North’s sole major ally, has grown increasingly frustrated with Pyongyang and has repeatedly called for restraint, urging all sides to negotiate to lessons tensions on the Korean peninsula. North Korean leader Kim Jong-un sends congratulations to Xi Jinping after congress Xi has previously sent messages to Kim, most recently last year when he expressed congratulations on the staging of a party congress in North Korea. A senior Chinese official also handed over a letter from Xi to Kim during celebrations to mark the 70th anniversary of the Korean Workers’ Party two years ago. Hwang Jae-ho, an expert on Northeast Asia regional security at Hankuk University of Foreign Studies in Seoul, said the exchange of messages between Kim and Xi meant the two nations did not want their ties to further deteriorate. “Under the current situation, relations between China and North Korea cannot worsen any more,” Hwang said. Wang Sheng, a professor studying Korean affairs at Jilin University in northeast China, said Xi’s reply was a courtesy to Kim. “The interaction reflected that Sino-North Korea relations may warm up a little because there is no major obstacle between two countries except Pyongyang’s nuclear programme,” he said.