Kim Jong Un
Kim Jong UnReuters

North Korean leader Kim Jong Un on Monday praised South Korea as very impressive after his sister and other top regime officials returned from their landmark visit to the Winter Olympics, AFP reported, citing the state-run KCNA news agency which published a short report on Kim meeting the delegation following its return to Pyongyang.

"After receiving the delegation's report, Kim Jong Un expressed satisfaction over it and said that very impressive were the features of the south side which specially prioritized the visit of the members of the DPRK side who took part in the Winter Olympics," KCNA said, adding the North Korean leader "expressed thanks" to Seoul.

Despite years of tensions between North and South Korea, South Korea's hosting of the Winter Olympics has sparked a sudden and rare moment of rapprochement between the two countries.

After months of rebuffing invitations from South Korea to attend the Olympics, Kim did an about-face in a New Year speech.

The North has since sent its athletes to the South Korean ski resort of Pyeongchang, along with cheerleaders and performers, and dispatched a diplomatic delegation that included Kim's sister Kim Yo Jong.

She became the first member of the North's ruling dynasty to set foot in the South since the end of the Korean War. She shook hands several times with the South's President Moon Jae-in, cheered a unified ice hockey team with him, and conveyed her brother's invitation to a summit in Pyongyang, noted AFP.

North Korea also recently sent a rare announcement addressed to “all Koreans at home and abroad”, saying they should make a “breakthrough” for unification without the help of other countries.

Monday's KCNA report suggested the North Korean leader wished to build on recent rapprochement, saying he felt it "is important to continue making good results by further livening up the warm climate of reconciliation and dialogue".

The report added that Kim "set forth in detail the orientation of the improvement of the north-south relations and gave important instructions to the relevant field to take practical measures for it," without detailing what those measures were.

Despite the rapprochement with South Korea, tensions continue between North Korea and the United States.

Kim claimed in January that his country has developed the capability to hit the entire U.S. mainland with its nuclear weapons.

U.S. President Donald Trump then tweeted in response, “North Korean Leader Kim Jong Un just stated that the ‘Nuclear Button is on his desk at all times.’ Will someone from his depleted and food starved regime please inform him that I too have a Nuclear Button, but it is a much bigger & more powerful one than his, and my Button works!”

Last year, North Korea tested ICBMs that had the potential range of reaching the United States mainland. Most recently, it launched a Hwasong-15 missile, a new type of ICBM which officials said can fly over 13,000 km (8,080 miles).

Pyongyang said following that launch as well that that it had test-fired its most advanced missile, putting the U.S. mainland within range, and also declared itself to be "a responsible nuclear power".