Multiple media outlets in South Korea report that North Korean leader Kim Jong Un is likely on his way to Russia.

Yonhap News Agency quoted government sources as saying intelligence authorities believe a train presumed to be carrying Kim is traveling to the Russian Far Eastern city of Vladivostok.

Major newspaper Dong-A Ilbo also says the train will likely cross the border into Russia as early as Tuesday morning.

There have been no announcements from the Russian and North Korean governments. This would be Kim's first visit to Russia in about four years, and his second overall.

Kim is expected to hold a summit with Russian President Vladimir Putin.