Kim Tells Putin N. Korea 'Fully Supports' Russia On Ukraine

North Korea fully supports Russia's war in Ukraine, leader Kim Jong Un told President Vladimir Putin on Wednesday during a state visit to Pyongyang, which has raised fears of more sanctions-busting military cooperation.

The two internationally isolated leaders, who greeted each other with a hug on the red carpet at the airport, signed a new "strategic partnership" deal during the trip, Putin's first to the nuclear-armed North since 2000.

The two countries have been allies since North Korea's founding after World War II and have drawn even closer as Russia seeks to forge a united front against the West.

Kim hailed a "new era" in bilateral relations Wednesday, saying "North Korea expresses full support and solidarity to the Russian government" over the war in Ukraine, which has triggered rafts of UN sanctions on Moscow.

Putin, in turn, thanked his host Kim -- himself under a decade-long UN sanctions regime over his banned weapons programs -- saying Moscow appreciated the "consistent and unwavering" support.

The United States and its allies have accused North Korea of providing ammunition and missiles to Russia for its war in Ukraine, and there are worries Putin's visit will lead to further military deliveries.

After a welcoming ceremony in Kim Il Sung square, featuring a military band and mass synchronised dancing, Putin invited his host to visit Moscow.

The summit, which included a lengthy one-on-one chat between the leaders, was their second meeting in a year.

Kim took his bulletproof train to Russia's far east last September for a summit with Putin at a space port.

Experts said the trip was really about defence ties, although the leaders might publicly highlight economic cooperation -- as any arms deals would flout UN sanctions.

"Russia requires North Korea's weapon support due to the prolonged war in Ukraine, while North Korea needs Russia's support in terms of food, energy, and advanced weapons," Koh Yu-hwan, North Korean studies emeritus professor at Dongguk University, told AFP.

"The military alliance aspect, however, should be viewed separately from what is publicly announced," he said, adding Moscow was cautious about "completely burning bridges with countries like South Korea."

Pyongyang has described allegations of supplying weapons to Russia as "absurd".

However, it thanked Russia in March for using its Security Council veto to effectively end monitoring of sanctions violations just as UN experts were starting to probe alleged arms transfers.

The United States voiced "concern" Monday about Putin's trip over the security implications for South Korea as well as Ukraine.

Putin's support allows Kim to "balance his reliance" on its other key ally Beijing, Vladimir Tikhonov, professor of Korean Studies at the University of Oslo, told AFP.

In return, Putin "gets secure access to Soviet-type artillery shells he needs in enormous quantities now," he added.

The two Koreas have remained technically at war since their 1950-53 conflict and the border dividing them is one of the most heavily fortified in the world.

Highlighting those security concerns, South Korea said its troops fired warning shots at soldiers from the North who accidentally crossed the border briefly on Tuesday and then retreated, during what Seoul said appeared to be efforts at border reinforcement.

In recent months, the North has torn up railway lines and removed streetlamps from roads that once connected the two Koreas, while laying more mines in what experts said was a symbolic campaign to show Seoul it was not open to diplomacy.

This week's visit is a way for Putin to thank the North "for acting as an 'arsenal for autocracy' in support of his illegal invasion of Ukraine," said Leif-Eric Easley, a professor at Ewha University in Seoul.

It is also part of Russia's drive to secure "strategic space" in Northeast Asia to counter US influence in the region, Seoul-based Institute for National Security Strategy's senior research fellow Kim Sung-bae told AFP.

"This intention is further evidenced by Putin's visit to Vietnam," he said, with the Russian leader set to fly to Hanoi after his trip to the North.