North Korean leader Kim Jong Un, in a letter to the head of the pro-Pyongyang General Association of Korean Residents in Japan, said he entrusts activities of the group to its chairman, who recently visited the North after Japan eased restrictions on travel between the countries in July, sources said Tuesday.

Ho Jong Man, chairman of Chongryon, as the diplomatically important entity is called in Korean, received the handwritten letter from Kim Yang Gon, a secretary of the Central Committee of the Workers' Party of Korea, while Ho was in North Korea from Sept. 6 to Oct. 7, the sources said.

The association has functioned as North Korea's de facto embassy in Japan for many decades in the absence of diplomatic relations between Tokyo and Pyongyang.

"As long as there is a leader (like Mr. Ho), the central party organization can forever trust Chongryon," Kim reportedly wrote.

The letter did not touch on the thorny issue of North Korea's past abductions of Japanese nationals, or the pending sale of the Chongryon headquarters building in Tokyo, the sources said.

In it, Kim apologized for not meeting with Ho during his first visit to North Korea in almost eight years.

Japan's sanctions on North Korea, imposed in 2006 following Pyongyang's missile launch and its first nuclear test, included a ban on re-entry into Japan by Chongryon executives. In early July, Japan lifted some sanctions against North Korea in return for the country's launch of a fresh investigation into Japanese nationals abducted by the North in the 1970s and 1980s.

Kim praised Ho in the letter for "fighting under difficult circumstances," and noted his decision to send a golden watch to the Chongryon head.

A public relations official of Chongryon said the association has no knowledge of the letter.