(2nd LD) S. Korean president expresses thanks for N. Korean leader's letter: presidential office

(ATTN: RECASTS headline, lead; ADDS more details, Moon's reaction throughout)

SEOUL, Dec. 30 (Yonhap) -- South Korean President Moon Jae-in on Sunday expressed gratitude to North Korean leader Kim Jong-un for sending a letter to call for continued efforts to build peace and prosperity on the Korean Peninsula.

Moon said South Korea "remains unchanged in welcoming" Kim's possible trip to Seoul and said he is very glad that Kim renewed his commitment to make joint efforts toward denuclearization.

"Even though there will be a lot of difficulties going forward, our hearts will be opened to each other depending on how much effort we make," Moon wrote in a Facebook message.

Moon's reaction came soon after South Korea announced that Kim sent a letter to Moon.

Kim said that the leaders of the two Koreas have taken practical measures this year helping to get over the long-running confrontation across their border, Cheong Wa Dae spokesman Kim Eui-kyeom told reporters.

The official said that the North Korean leader expressed disappointment for not making his promised trip to Seoul by year's end but emphasized a strong willingness to honor the promise while closely watching relevant situations.

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