The journey from the train station in Khasan, near the North Korean border, to Vladivostok took about nine hours.

After crossing the Russian border, Kim stopped at the Khasan station where was presented with flowers as well as bread and salt -- a Russian tradition for welcoming guests -- local lawmaker Natalia Karpova told Russian state news agency TASS.

Kim said he was "happy to be on Russian soil," the Russian region of Primorsky reported on its official website.

"I came to Russia with the warm feeling of our people," Kim told state-run Russia 24 upon arrival. "I hope that this visit will be successful and useful, and that during the negotiations with esteemed President Putin, I will be able to specifically discuss issues of resolving the situation on the Korean Peninsula and developing our bilateral relations."

Timing of talks significant

Kim's visit to North Korea's northern neighbor comes amid an impasse in the nuclear negotiations between Pyongyang and Washington. Trump and Kim's Hanoi meeting ended early without an agreement, with the two sides seemingly far apart on how to trade sanctions relief for meaningful steps toward denuclearization.

A State Department spokesperson said the United States is aware of the reports that Kim has left for Russia.

"The United States and the international community is committed to the same goal -- the final, fully verified denuclearization of North Korea. It is Chairman Kim's commitment to denuclearization upon which the world is focused."

Kim himself said there could be repercussions if talks continue to stall during a meeting of North Korea's rubber-stamp parliament earlier this month.

Analysts have speculated that Kim's meeting with Putin could be a way for the young North Korean leader to assess his diplomatic options outside talks with the United States.

North Korea may hope for Russian support in pressuring Washington over sanctions relief, which continues to be a major sticking issue in talks between the two sides. The Trump administration has said sanctions will only be lifted after North Korea gives up its nuclear weapons program.

Pyongyang also may be seeking to lessen its economic reliance on Beijing, North Korea's only significant trading partner. Former North Korean leader Kim Il Sung was notorious for playing China and the Soviet Union off each other in order to maximize foreign investment.