N. Korean leader Kim Jong

This April 24, 2019 file photo released by press office of the administration of Primorsky Krai region, shows North Korea's leader Kim Jong-un leaving a train carriage after arriving at the border station of Khasan, Primorsky Krai region, Russia. AP-Yonhap

A special train believed to be carrying North Korean leader Kim Jong-un appears to have departed for Russia, a South Korean government official said Monday.

"The intelligence authorities believe the train presumed to be carrying Kim Jong-un is moving to Vladivostok," the official told Yonhap News Agency.

Another senior official confirmed that Kim appears to have departed Pyongyang and is headed to Russia.

Still, there has been no word from Pyongyang and Moscow on Kim's possible trip to Russia.

North Korea has yet to disclose whether its leader has started his possible train trip, which is expected to take 20 hours or more.

The New York Times has reported that Kim plans to travel to Vladivostok, possibly by armored train this month, for talks with Putin about the possibility of supplying Russia with more weaponry for its war in Ukraine and other military cooperation.

Earlier in the day, Russia's Interfax news agency reported that Kim is likely to visit Russia's Far East "in the coming days," citing multiple regional sources.

South Korea's defense ministry also said Monday it sees the "possibility" of a summit between Kim and Putin.

The assessment came amid media reports that Kim and Putin could hold a summit on the sidelines of an economic forum in Vladivostok this week.

If confirmed, the trip would mark the first such visit to Russia by Kim in nearly 4 1/2 years and his first trip abroad since the outbreak of the COVID-19 pandemic.

Pyongyang has recently been seeking to bolster military ties with Moscow in the wake of growing security cooperation among South Korea, the United States and Japan. (Yonhap)