Meanwhile, the leaders of North Korea and China exchanged letters on Sunday... as their countries mark 70 years of diplomatic ties.
In the letters, they promised to make those ties even closer.
Lee Seung-jae has more.
North Korea's state-run Korean Central News Agency reported Sunday that the leaders of the two communist allies exchanged letters of greeting earlier in the day to mark 70 years of their countries' bilateral ties.
In his letter to President Xi Jinping,... Kim Jong-un described the establishment of their diplomatic ties as an "epochal event",... adding that their friendship will be "immortal".
The North Korean leader added Pyeongyang-Beijing relations have entered a "crucial period",... and he promised to carry forward the "excellent traditions" for their friendship that is "envied by the world."
In his letter to Kim,... President Xi called their relations, a "valuable asset" that binds the two countries,... adding it's the "consistent and firm policy of" China to "consolidate and develop" its relations with its ally,... as the North was among the first countries to establish diplomatic relations with China.
The two sides have been strengthening their ties in recent months,... with the two leaders holding five rounds of summit talks since March last year.
That includes President Xi's visit to the North Korean capital in June,... marking the first trip by a Chinese head of state to North Korea in 14 years.
Earlier on Sunday,... the North's state-run newspaper, the Rodong Sinmun,... issued a commentary,... vowing to develop bilateral ties with China,... "regardless of the international situation".
Lee Seung-jae, Arirang News.