-North Korea talks. The U.S. State Department has not commented on the report of Kim's message.
There was speculation that the letter was delivered via a hotline between South Korean National Intelligence Service chief Suh Hoon and Kim Jong-un's right-hand man Kim Yong-chol.
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.
The spokesman said the office summarized Kim's two-page letter and paraphrased it in different words and what he said wasn't a direct quote from the North's leader as it is a violation of diplomatic custom.
In the letter, Kim expressed appreciation for the three summits between the countries that were held in 2018 and said he regretted not being able to make it to Seoul for a fourth summit, according to The Associated Press. It was the first time a member of the ruling Kim dynasty had visited the South since the 1950-1953 Korean War.More news: Ultima Thule already looks weird in first image
More news: Sheriff Blames Sanctuary State Laws For Officer's Death
More news: Fake Alexa setup app is in App Store, ranked #6 in Utility
Moon welcomed the latest message, saying the North's leader had also expressed "active intention to carry out agreements" made in his previous summits with the USA and the South, without elaborating further.
Chairman Kim also expressed his intentions to meet President Moon frequently again in 2019 to advance discussions on the Korean Peninsula's peace and prosperity and discuss issues on the denuclearization of the Korean Peninsula, ' the spokesman said.
Talks between the US and North Korea have made little progress since Trump and Kim held an unprecedented summit in June and signed to "work toward complete denuclearization of the Korean Peninsula", without defining the term or setting a deadline.
The meetings followed a rollercoaster few years of relations between US President Donald Trump and Kim - nosediving with Trump's famous "Rocket man" speech at the United Nations General Assembly in 2017, and peaking with their highly anticipated summit in Singapore earlier this year.
It was nearly exactly one year ago, in the wake of Kim's 2018 policy speech, that Trump threatened the North Korean dictator and said his nuclear button was "much bigger and more powerful". The two sides have clashed over the pace and sequence of talks, with North Korea demanding relief from worldwide sanctions and the USA seeking more steps toward disarmament.