A senior North Korean official left for Vladivostok after ending his five-day trip to Moscow amid speculations that the trip is part of preparations for a possible visit to Russia by the North's leader Kim Jong-un.

Kim Chang-son, the official with the North's State Affairs Commission, was seen at Sheremetyevo International Airport in the Russian capital city at around 2:45 p.m. Saturday.

A Russian flight carrying Kim took off at 4:10 p.m. and was expected to land in Vladivostok at 7:40 a.m. Sunday. Kim is likely to head home on Monday via an Air Koryo flight.

The visit by Kim, known as leader Kim Jong-un's de facto chief of staff, raised speculation that Pyongyang could be making preparations for leader Kim's first trip to Russia since taking office.