SEOUL: Russian President Vladimir Putin signed a mutual defence agreement on Wednesday with North Korea’s Kim Jong Un, who offered his “full support” on Ukraine.

The pledge of military cooperation was part of a strategic treaty signed during a summit in Pyongyang, where Putin was making his first visit in 24 years.

“It is really a breakthrough document,“ Putin said at a news conference in the North Korean capital, adding it provided, “among other things, for mutual assistance in case of aggression against one of the parties”, Russian news agencies said.

The two countries have been allies since North Korea’s founding after World War II and have drawn even closer since Russia’s 2022 invasion of Ukraine.

The United States and its allies have accused North Korea of providing ammunition and missiles to Russia for its war in Ukraine, and the treaty was certain to fuel concerns of more deliveries.

Putin also said Russia “does not rule out military-technical cooperation with the DPRK in connection with the treaty”, referring to North Korea by its official name.

Kim called Putin the “dearest friend of the Korean people” and said his country “expresses full support and solidarity to the Russian government” over the war in Ukraine, which has triggered rafts of sanctions on Moscow.

Putin, in turn, thanked Kim -- whose country has been under a UN sanctions regime since 2006 over its weapons programmes -- saying Moscow appreciated the “consistent and unwavering” support.

The two countries would not tolerate Western “blackmail”, Putin said, calling for a review of UN sanctions on North Korea.

“The indefinite restrictive regime inspired by the US and its allies at the UN Security Council towards the DPRK should be reviewed,“ Putin said.

“Today, we are fighting together against the hegemonism and neo-colonial practices of the United States and its satellites,“ the Russian leader added.

Putin later flew to Vietnam to begin a state visit, with AFP video footage showing him departing his plane in Hanoi early Thursday morning.

- Red carpet -

Kim greeted Putin upon his pre-dawn arrival at a Pyongyang airport on Wednesday, with the pair embracing and smiling.

They then attended a welcoming ceremony in Kim Il Sung Square, featuring a military band and mass synchronised dancing, after which Putin invited Kim to visit Moscow.

Putin gifted his host a luxury car by Russian carmaker Aurus, and took him for a drive, according to state-run RIA Novosti news agency.

The two also visited an Orthodox Church in Pyongyang, it added.

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 in September for a summit with Putin at a spaceport.

Kim said the two countries’ ties had now risen “to a new high of alliance”.

“It is greatly satisfying to conclude a great treaty that befits a changed international situation and the strategic nature of new DPRK-Russia relations,“ he said.

Kim also said the new treaty “fully contributes to maintaining peace and stability in the region”.

The US State Department, when asked by AFP about Putin’s visit, said “deepening cooperation between Russia and the DPRK is a trend that should be of great concern to anyone interested in maintaining peace and stability on the Korean Peninsula”.

The spokesperson added: “As we have said before, we don’t believe any country should give Mr. Putin a platform to promote his war of aggression against Ukraine. Russia is blatantly violating the UN Charter and working to undermine the international system.”

Mykhailo Podolyak, a senior aide to Ukraine’s President Volodymyr Zelensky, told AFP that North Korea was abetting Russia’s “mass murder of Ukrainians”, and called for greater international isolation of both countries.

- ‘Arsenal for autocracy’ -

Vladimir Tikhonov, professor of Korean Studies at the University of Oslo, said Russia would now “largely sabotage the sanctions regime around North Korea, in deed if not in word”.

The new mutual support clause is “a reminder to Americans that Russia may complicate their lives if they support Ukraine too enthusiastically”, he told AFP, pointing to the roughly 28,000 US troops based in South Korea, a key regional security ally of Washington.

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.

This week’s visit was 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 was also part of Russia’s drive to secure “strategic space” in Northeast Asia to counter US influence in the region, Kim Sung-bae, a research fellow at the Seoul-based Institute for National Security Strategy, told AFP.

“This intention is further evidenced by Putin’s visit to Vietnam,“ he said.