Xi thanks Kim for 'fruitful' summit: KCNA

North Korean leader Kim Jong-un, right, and Chinese President Xi Jinping walk following a concert welcoming the Chinese leader at a gymnasium in Pyongyang, Monday, in this photo released by the North's official Korean Central News Agency the next day. Yonhap

North Korean leader Kim Jong-un has received a letter from Chinese President Xi Jinping thanking him for "fruitful" summit talks and warm hospitality, Pyongyang's state media reported Wednesday.

In the letter, Xi said the two leaders had exchanged views "in-depth" and reached "important common understanding" on issues of shared concerns that he said added "new substance" to relations between their countries, according to the report by the Korean Central News Agency (KCNA).

Describing the relationship as having entered "a new historical journey," Xi said he was ready to work with Kim to consolidate and develop ties and advance the socialist cause of both countries.

Xi returned to Beijing the previous day after his two-day state visit to Pyongyang, his first trip to the North in nearly seven years.

Kim and Xi pledged to deepen and expand exchanges across politics, economy, culture and science, and to step up high-level contacts between the two sides. Neither side, however, made any mention of North Korea's nuclear program or the security situation on the Korean Peninsula.