"It has a positive message through which North Korea's directions and intentions on inter-Korean relations and denuclearization of the Korean Peninsula as well as Chairman Kim Jong-un's trip could be read," a source quoted Moon as saying during a meeting with ruling party leaders.

The president was also said to explain that the presidential office decided to make public the content of Kim's letter as it determined that the letter had special meaning. The disclosure was made after getting an understanding from the North, Moon was quoted as saying.

He didn't provide other details in the letter.

Hours after its disclosure on Sunday, Moon hailed Kim's renewed commitment to denuclearization.

Moon and Kim met three times this year in which they agreed to complete denuclearization of the Korean Peninsula and to cooperate in easing tensions and bolstering cross-border exchanges.

Kim reaffirmed his commitment to denuclearization in his first-ever summit with U.S. President Donald Trump in June.

Denuclearization talks, however, have been in a stalemate as Pyongyang wants sanctions relief for subsequent steps following the summit, while Washington is asking for more concrete measures before making major concessions.

The letter was sent two days before leader Kim is expected to deliver his New Year's speech on Tuesday, which will be closely watched by the outside world for any clues as to the North's policy directions on denuclearization and inter-Korean relations. (Yonhap)