MOSCOW – North Korean leader Kim Jong Un inspected a Russian fighter jet factory that is under Western sanctions on Friday, part of a visit Washington and its allies fear could strengthen Russia’s military in Ukraine and bolster Pyongyang’s missile programme.

Russian President Vladimir Putin had discussed military matters and deepening cooperation with Mr Kim when they met in a summit on Wednesday.

South Korea and the United States said on Friday that military cooperation between North Korea and Russia was a violation of United Nations sanctions and that the allies would ensure there is a price to pay.

Mr Kim, 39, on Friday visited aviation facilities in the far eastern city of Komsomolsk-on-Amur, the Yuri Gagarin Aviation Plant and the Yakovlev plant, both units of United Aircraft Corporation, which is sanctioned by the West over the war in Ukraine.

At the Gagarin plant, which is also specifically sanctioned by the US, Mr Kim inspected the assembly workshops where the Sukhoi Su-35 multirole fighter and the Su-57 fighter are made, escorted by Deputy Prime Minister Denis Manturov, the government said.

Mr Kim, dressed in a suit and accompanied by North Korean military officials in uniform, was shown on Russian state television carefully inspecting the cockpit of a fighter jet as Russian officials explained its capabilities via a translator.

He then inspected workshops where the fuselage compartments and wing assemblies of Russia’s Sukhoi Superjet 100 are made before watching a demonstration flight of the Su–35. He nodded with approval as the fighter performed.

Russia has gone out of its way publicise the visit and to drop repeated hints about the prospect of military cooperation with North Korea, which was formed in 1948 with the backing of the Soviet Union.

For Mr Putin, who says Russia is locked in an existential battle with the West over Ukraine, courting Mr Kim allows him to needle Washington and its Asian allies while potentially securing a deep supply of artillery for the Ukraine war.

Washington has accused North Korea of providing arms to Russia, which has the world’s biggest store of nuclear warheads, but it is unclear whether any deliveries have been made.

US warning

Mr Putin and Mr Kim called each other “comrades” when they met at Russia’s most advanced space rocket launch cosmodrome on Wednesday, with Mr Kim toasting to Mr Putin’s health and victory for Russia in Ukraine.

The US and South Korea appear worried by the revival of Moscow’s friendship with Pyongyang which they fear could give Mr Kim access to some of Russia’s sensitive missile and other technology.

US and South Korean officials called on Moscow to show responsibility as a permanent member of the UN Security Council.

“We agreed to work together to ensure there is a price to pay for the grave violation of Security Council resolutions,” South Korean Vice Foreign Minister Chang Ho-jin told a press conference in Seoul.

There was no comment from either Mr Kim or Mr Putin on the US warnings, though Russian diplomats pushed back against the criticism.

They said that Washington had no right to lecture Moscow after the United States had bolstered its allies across the world, including with a visit of a US nuclear-armed ballistic missile submarine to South Korea in July.

The US State Department said on Wednesday the Biden administration would not hesitate to impose additional sanctions on Russia and North Korea if they conclude new arms deals.

The Kremlin says it abides by UN sanctions but that it has a right to develop neighbourly relations, including on sensitive topics.

Mr Kim arrived in Russia on his special train on Tuesday, held a summit with Mr Putin on Wednesday in Vostochny and appeared to have spent most of Thursday travelling before appearing in Komsomolsk-on-Amur, 6,000km east of Moscow, on Friday.

His Maybach limousine was filmed being driven onto his train on Friday in Komsomolsk-on-Amur with the help of a special platform. REUTERS