The United States and the United Kingdom have expressed concerns that Kim could provide weapons and ammunition to Russia, which has expended vast stocks in more than 18 months of war in Ukraine. Moscow and Pyongyang have denied such intentions.

The US Department of State said on Wednesday that US President Joe Biden’s administration “won’t hesitate” to impose more sanctions on Russia and North Korea if they conclude any new arms deals.

State Department spokesperson Matthew Miller issued the warning at a briefing in response to questions about the meeting in Russia between Russian President Vladimir Putin and North Korean leader Kim Jong Un.

“We have taken a number of actions already to sanction entities that brokered arms sales between North Korea and Russia and we won’t hesitate to impose additional actions if appropriate,” Miller said.

It was troubling that Russia and North Korea are discussing increased cooperation that could violate UN Security Council resolutions, he said.

“When you see what looks to be increased cooperation and probably military transfers, that is quite troubling and would potentially be in violation of multiple UN Security Council resolutions,” Miller said.

James O’Brien, head of the Office of Sanctions Coordination, told The Associated Press news agency such a deal would trigger a US attempt to identify the individuals involved and the financial mechanisms they used to “at least limit their ability to be effective”.

“Russia is scraping the bottom of the barrel looking for help because it’s having trouble sustaining its military,” he said. “Russia is now overtly engaging with a country that the UN has sanctioned. And that’s very problematic for Russia’s global position.”

During the meeting, which lasted more than four hours at Russia’s spaceport in the Far East, Putin showed Kim around Russia’s most advanced space rocket launch site in the region, and discussed the possibility of sending a North Korean cosmonaut into space.

Kim, who arrived by train from North Korea, asked detailed questions about rockets as the two leaders toured the Vostochny Cosmodrome.

When asked by Russian media, who were given significant access at the summit, if Russia would help Kim build satellites, Putin said, “That’s why we came here.”

Across the Atlantic, the United Kingdom also urged North Korea to end arms talks with Russia and said Kim’s visit showed how isolated Moscow has become on the world stage.

“We urge the DPRK to cease its arms negotiations with Russia and to abide by public commitments Pyongyang has made not to sell arms to Russia,” Prime Minister Rishi Sunak’s spokesperson told reporters.

“This visit serves to highlight Russia’s isolation on the global stage, and as the world unites against Putin’s illegal invasion of Ukraine and he has been forced to turn to regimes such as North Korea.”

Putin gave numerous hints that military cooperation was discussed but disclosed few details. Defence Minister Sergey Shoigu attended the talks. The Kremlin said sensitive discussions between neighbours were a private matter.

During a news briefing on Wednesday, UN Secretary-General Antonio Guterres also signalled that Moscow had to tread carefully.

“Any form of cooperation of any country with North Korea must respect the sanctions regime that was imposed by the Security Council,” Guterres told reporters, adding that it was “extremely relevant” in the case of Russia and North Korea.

‘Comrades’

Reporting from Seoul, Al Jazeera’s Florence Looi said it was significant that Kim Jong Un had chosen Putin to be the first foreign leader that he has met since the pandemic.

Looi also explained what North Korea and Russia’s closer ties will look like after the meeting between the two leaders.

“North Korea is one of the few countries to publicly support Russia in its invasion and war in Ukraine. Now, Kim has stated that he considers this war a righteous endeavour, and he also said that North Korea is ready to stand with Russia, against imperialism,” Looi said.

The two leaders called each other “comrades” at lunch and Putin repeatedly reminded Kim that it was the Soviet Union that backed North Korea – and was first to recognise it just more than 75 years to the day since it was established.

Russia has joined China in opposing new sanctions on North Korea, blocking a US-led push and publicly splitting the UN Security Council for the first time since it started punishing Pyongyang in 2006.

Asked about military cooperation, Putin said Russia complied with international rules but that there were opportunities to explore.