North Korean leader Kim Jong Un's train "appears" to have departed for Russia, possibly for a summit with President Vladimir Putin, multiple South Korean media outlets reported Monday, citing unidentified officials.
US and other officials told The New York Times at the weekend that Kim, who rarely leaves North Korea, was soon likely to head by armoured train to Vladivostok, on Russia's Pacific coast, for arms talks with Putin.
"Intelligence authorities believe the train presumed to be carrying Kim Jong-un is moving to Vladivostok," an unidentified official told Yonhap new agency.
Another senior official told Yonhap Kim "appears" to have left Pyongyang and was en route to Russia.
Kim has not travelled outside North Korea since the start of the coronavirus pandemic.
Broadcaster YTN said Seoul "expects that Chairman Kim will hold a meeting with President Putin of Russia around the day after tomorrow", meaning Wednesday.
Moscow, a historical ally of Pyongyang, was a crucial backer of the isolated country for decades and their ties go back to the founding of North Korea 75 years ago.
Kim has been steadfast in his support for Moscow's invasion of Ukraine, including, Washington says, supplying rockets and missiles.
In July, Putin hailed Pyongyang's "firm support for special military operations against Ukraine".
Experts suggest that Putin is seeking artillery shells and antitank missiles from North Korea, while Kim is reportedly in search of advanced technology for satellites and nuclear-powered submarines, as well as food aid for his impoverished nation.
Vladivostok will be hosting the Eastern Economic Forum until Wednesday.
The Kremlin has refused to confirm any meeting between Putin and Kim on the sidelines of the summit, which was attended by 68 nations last year.
'Pay a price'
The White House warned last week that Pyongyang would "pay a price" if it supplies Moscow with weaponry for its war in Ukraine.
Washington said Russia could use weapons from North Korea to attack Ukrainian food supplies and heating infrastructure heading into winter to "try to conquer territory that belongs to another sovereign nation".
Andrei Lankov, a North Korea expert at Kookmin University in Seoul, told AFP that the possible Putin-Kim summit was part of "gentle diplomatic blackmail" by Moscow of Seoul because Russia did not want South Korea to supply weapons to Kyiv.
Seoul is a major arms exporter and has sold tanks to Kyiv's ally Poland, but longstanding domestic policy bars it from selling weapons into active conflicts.
"The major worry of the Russian government now is a possible shipment of the South Korean ammunition to Ukraine, not just one shipment but a lot of shipments," Lankov said.
Cheong Seong-chang, researcher at the Sejong Institute, told AFP that, were North Korea to expand military cooperation with Russia, "there is an increased likelihood of prolonged conflict in Ukraine".
And Pyongyang's reward for aiding Moscow could mean that "advancements in North Korea's nuclear submarine and reconnaissance satellite development might then progress at a faster pace", he said.
Kim has become well-known for his preference for train travel when it comes to international trips. His father and predecessor, Kim Jong Il, was famously scared of flying.
The current leader reportedly lacks confidence in his private jet and harbours "concerns about the potential for aerial bombing by Washington", said Yang Moo-jin, president of the University of North Korean Studies in Seoul.
In 2019, he made the 60-hour return train trip from Hanoi to Pyongyang by train after a summit with then-US president Donald Trump collapsed, and reportedly hinted at physical fatigue from spending hours on the rails.