PYONGYANG - Kim Jong-un, top leader of the Democratic People's Republic of Korea, clapped his hands and said he was "deeply moved" as he, along with his wife and hundreds of other DPRK citizens, watched a rare performance by pop stars from the Republic of Korea in Pyongyang. The concert highlights a thawing ties between the two neighbors which are technically still at war after the 1950-53 Korean War ended with a cease-fire rather than a peace agreement.

During Sunday's performance at the packed 1,500-seat East Pyongyang Grand Theater, local concertgoers most of the men in dark suits but some women in colorful traditional "hanbok" dresses waved their hands from their seats when the ROK stars joined together to sing a popular Korean song, Our wish is unification. After the two-hour performance ended, the DPRK audience gave a thundering standing ovation.

A ROK artistic group, including some pop legends and the popular girl band Red Velvet, flew to Pyongyang over the weekend for two performances in the DPRK capital, one on Sunday and the other on Tuesday. How DPRK citizens would react to Red Velvet was a focus of keen media attention in the ROK. Red Velvet has more than 4.6 million followers on Instagram.

Kim, wearing a dark suit, made a surprise visit to the performance with his wife Ri Sol-ju, sister Kim Yo-jong and other senior officials, including nominal head of state Kim Yong-nam. Kim Jong-un applauded during the event and shook hands with the ROK performers. He also took a group photo with them after their performance, according to DPRK's state news agency. Kim Jong-un said "he was deeply moved to see our people sincerely acclaiming the performance, deepening the understanding of the popular art of the ROK side", the DPRK's Korean Central News Agency reported.

"We should hold culture and art performances frequently," Kim said. Mentioning the performance's title, Spring comes, Kim also asked the performers to tell ROK President Moon Jae-in that the two countries should hold a similar event in Seoul in the autumn, according to ROK media pool reports.

Kim also talked about Red Velvet.

"There had been interest in whether I would come and see Red Velvet. I had initially planned to attend a performance the day after tomorrow, but I came here today after adjusting my schedule," Kim was quoted as saying. "I thank you for this kind of gift to Pyongyang's citizens."

It was the first time for a DPRK top leader to attend such a ROK performance in Pyongyang. During a past period of detente, the ROK occasionally sent pop singers to the DPRK, but that stopped in 2005.

Seulgi, band member of Red Velvet, said she cried when all people sang together the song, Our Wish is Unification.

The ongoing cooperation steps between the neighbors began after Pyongyang took part in February's Winter Olympics in Pyeongchang. During the games, a DPRK art troupe performed in the ROK, and Moon and his wife watched it with visiting senior DPRK officials including Kim Yo-jong.

Kim Jong-un is to meet Moon at a border village on April 27 and US President Donald Trump in May in separate talks.

AP, Reuters and Xinhua contributed to this story.