US officials have warned in recent days that arms negotiations between Russia and North Korea are actively advancing, and a report this week said that North Korea’s Kim Jong-un plans to travel to Russia this month to meet President Vladimir Putin and discuss supplying Moscow with weapons for its war effort.

Harris, who was in Indonesia for an Asean summit, told CBS News in an interview broadcast on Thursday that it would be a sign of desperation for Russia to seek aid from reclusive North Korea and it would further isolate both countries.

“I think it would be a huge mistake. The idea that they would be supplying ammunition to that end, it would be a huge mistake. I also believe very strongly that for both Russia and North Korea, this will further isolate them,” Harris said.

White House national security adviser Jake Sullivan said on Tuesday that arms negotiations between Russia and North Korea were actively advancing and warned Kim that his country would pay a price for supplying Russia with weapons to use in Ukraine.

Last month, Washington imposed sanctions on entities it accused of being tied to arms deals between North Korea and Russia.

Sydney Seiler, who retired this summer as National Intelligence Officer for North Korea at the US National Intelligence Council, told a Washington think-tank that, for Kim, a potential meeting with Putin “seems to be the result of a calculation that there’s something to be had from this in the near term.

“The worst-case scenario is that this … relationship between Russia and North Korea goes to the next level,” he said.

Against that, however, were traditional limitations on the support Russia has provided to North Korea – which has developed a sophisticated ballistic missile and nuclear arms programme despite international sanctions – and Moscow’s adherence to the goal of a denuclearised Korean peninsula.

“The good news is, my thoughts are [that] a lot of those traditional limitations or parameters … will serve as a limiting factor,” Seiler said.

He said Kim could be looking to fill shortfalls in military resources across the board and in food supplies as the country emerges from a long shutdown during the Covid-19 pandemic.

“The substance of what North Korea is able to get out of Russia is going to be crucial in determining its strategic impact,” Seiler said. “Is it food, is it supplies, is it linked to some material necessary to restart factories, or feed munitions assembly lines?

“Or is Russia out to really enhance North Korea’s capabilities … [amid] concerns over support to the missile programme, nuclear programme, conventional programme?”

Seiler said Russia could perhaps agree to provide North Korea with satellite imagery until Pyongyang manages to put its own military satellite into space.

“All this stuff is potentially troubling,” he said.

(Reporting by Doina Chiacu and David Brunnstrom; Editing by Andrea Ricci and Sandra Maler.)