North Korean leader Kim Jong Un has sent a letter to Japan’s most influential pro-Pyongyang group, hailing its past achievements and pledging protection for it and all Koreans in Japan, North Korean state media said Tuesday.

The long letter, released in English by the Korean Central News Agency, was sent Monday on the occasion of the 60th anniversary of the foundation of the General Association of Korean Residents in Japan, commonly known as Chongryon.

“In the face of difficult conditions in an alien land, (Chongryon) brings up the children of Korean compatriots into true patriots through its well-knit network of national education ranging from primary school to university,” Kim said, according to the transcript provided by KCNA.

The letter praises Chongryon for its fidelity to North Korea, saying Pyongyang has the “greatest pride” in the group being “boundlessly faithful to its leaders, homeland and nation.”

Kim said the group has aided North Korea’s prosperity and urged it to recruit more businesspeople in its work. He said they and others “should devote their patriotic efforts to the sacred cause of achieving the prosperity of their socialist motherland.”

The letter also says the group should “develop friendly ties” with “progressive (Japanese) personages” to create favorable conditions for its development and promotion of bilateral ties.

“Our Party and the government of (North Korea) will take care, on its own responsibility, of the destiny and future of Chongryon” and do its “best for the development of the movement of Koreans in Japan,” Kim added.

North Korea has strongly criticized the arrest by Japanese police earlier this month of the son of the association’s leader in connection with alleged illegal imports of mushrooms.

North Korea, which resumed official talks with Japan about a year ago, has seen the arrest as an “unpardonable provocation” and threatened that it will have negative repercussions on bilateral relations.

Kim did not address the arrest in the letter, but extended “compatriotic greetings to Chongryon officials including Chairman Ho Jong Man and to all other compatriots in Japan.”