North Korean media have not reported yet on a personal letter that leader Kim Jong-un sent to South Korean President Moon Jae-in this week in a surprise conciliatory gesture amid long-stalled relations between the two sides.

Kim sent the letter on Wednesday to express his support for South Korea's fight against the new coronavirus, the presidential office Cheong Wa Dae said the following day. In return, Moon sent a response letter to thank Kim for his support, the office added.

But North Korean state media outlets have not reported on Kim's message yet.

That compares with the relatively open reporting in 2018 when Kim sent a message to Moon via Kim Yo-jong, his sister and closest aide, when she visited Seoul to participate in the PyeongChang Olympics amid a reconciliatory mood in inter-Korean relations.

Kim's latest letter has given rise to diverse interpretations, as it came just one day after his sister issued a harshly worded statement criticizing the presidential office for complaining about the North's recent launches of short-range missiles.

Given that Kim's actions are usually covered by North Korean media the following day, it seems unlikely that state media will report on the message.

The lack of coverage could be interpreted as the North adopting a stance of strategic ambiguity, giving wriggle room for inter-Korean relations to either improve or deteriorate depending on how the political situation plays out.

Denuclearization talks have been stalled since Kim and US.

President Donald Trump failed to narrow their differences on how to math out Pyongyang's steps toward removing nuclear weapons at the Hanoi summit in February last year.

The letters are the first such exchange between Moon and Kim this year. (Yonhap)