Seoul, Oct 10 : In a letter to North Korean leader Kim Jong-un marking the 75th founding anniversary of the ruling Workers' Party of Korea (WPK), Chinese President Xi Jinping vowed efforts to further develop relations between Beijing and Pyongyang, state-media reported on Saturday. "In recent years under the reliable leadership of the Central Committee of the WPK headed by Comrade Chairman, the Party and people of Korea have put efforts on strengthening the Party building and the economic work, have coped with all sorts of hardships and challenges in single-minded unity and conducted active exchange and cooperation with foreign countries to make a series of important achievements, while making steady advance along the path of socialism," Pyongyang's Korean Central News Agency (KCNA) quoted Xi as saying in the letter. China is North Korea's largest neighbour and trade partner, accounting for more than 80 per cent of Pyoungyang's overall imports and exports, reports Yonhap News Agency. In his letter, Xi added that China-North Korea relations have reached a "new historic page" following his meetings with Kim in recent years. "We have an intent to successfully defend, consolidate and develop China-Korea relations together with Korean comrades and propel the long-lasting and stable development of the socialist cause of the two countries and thus provide the two countries and the two peoples with greater happiness and make new and active contributions to realizing regional peace, stability, development and prosperity," he said. Between 2018 and 2019, Kim and Xi met five times. The March 25Â?28, 2018 meeting was Kim's first diplomatic trip abroad to meet a foreign leader since coming to power in 2011. /IANS