President Moon Jae-in will send National Intelligence Service Director Suh Hoon and chief presidential security adviser Chung Eui-yong as his special envoys to North Korea.

An official at the presidential office said on Sunday that Suh and Chung will soon be dispatched to Pyongyang as joint chiefs of a South Korean delegation, adding that the full list of the delegation will be released later on Sunday.

The dispatch, which will reciprocate the recent visit by North Korean leader Kim Jong-un's sister Kim Yo-jong to the 2018 PyeongChang Olympics, will likely come early this week.

It is unprecedented for South Korea to send two special envoys to North Korea.

There are speculations that the two envoys will deliver Moon's letter to the North Korean leader during their trip to Pyongyang.

Right after the trip, Chung is expected to visit Washington to explain the outcome of the trip and discuss South Korea-United States cooperation on North Korean issues.