Supreme Leader Kim Jong-un of North Korea sent a series of letters to South Korean outgoing President Moon Jae-in with a rare tone of appreciation.

Kim, the totalitarian dictator of North Korea, is not known for his kindness toward the leadership of South Korea. However, in a correspondence with Moon over the course of several weeks, Kim wrote warm words of diplomacy rarely seen between the fractured countries.

"Kim Jong Un appreciated the pains and effort taken by Moon Jae-in for the great cause of the nation until the last days of his term of office," North Korean state media said of the messages, calling them an "expression of their deep trust."

Moon confirmed the exchange of letters and spoke optimistically about the possibility of a reunified Korea in the future.