North Korea's Kim praises South's departing Moon

STORY: In a rare bout of friendly exchange, North Korea's leader Kim Jong Un reportedly traded letters this past week with South Korea's outgoing President Moon Jae-in.

The letters, reported by North Korean state media KCNA and confirmed by Moon's office, come despite strained border ties and flaring tensions over Pyongyang's recent weapons tests.

KCNA said Moon sent a letter to Kim on Wednesday in which he promised to continue pushing for unification, based on joint declarations reached at the Inter-Korean summits of 2018, despite calling the situation 'difficult'.

Kim reportedly replied on Thursday that their summits were 'historic' and 'gave people hope for the future'.

And on Friday, KCNA said Kim thanked Moon for trying to improve relations between the two countries, calling the letter exchange an expression of 'deep trust'.

Moon is set to step down in May.

He urged Kim on Friday to commit to talks under his replacement, President-elect Yoon Suk-yeol.

South Korean Presidential Blue House Spokesperson, Park Kyung-Mee.

"President Moon said the progress of dialogue is now up to the incoming government, and he hopes that Chairman Kim to keep following a great cause of peace in the Korean peninsula and commit to inter-Korean cooperation."

Moon staked his legacy on improving inter-Korean ties, and helped arrange unprecedented meetings between Kim and then-U.S. President Donald Trump in a bid to denuclearise the Korean Peninsula.

However those talks ultimately failed, and relations between the two Koreas deteriorated, with Pyongyang criticizing what it called Seoul's 'double standards' over its weapons development.

Tensions sharply escalated last month after North Korea launched intercontinental ballistic missiles, breaking a self-imposed 2017 moratorium, with concerns that it may also restart its nuclear tests.

South Korean and U.S. troops also began their annual joint military drills this week, which North Korea routinely denounces as rehearsals for war.