Kim Jong Un could travel to Russia to meet president Vladimir Putin, according to a US official.
The North Korean leader could make the trip as early as this month, according to the unnamed source, with the port city of Vladivostok, near to the border between the two countries, believed to be a possible meeting point.
It comes as the US claims the Kremlin is attempting to acquire military equipment for its war in Ukraine.
National Security Council spokeswoman Adrienne Watson said on Monday that Russian defence minister Sergei Shoigu had travelled to North Korea's capital of Pyongyang last month.
It is believed Mr Shoigu attempted to persuade North Korea - one of the most militarised countries in the world - to sell artillery ammunition to Russia.
Ms Watson said: "We have information that Kim Jong Un expects these discussions to continue, to include leader-level diplomatic engagement in Russia."
She added that the US is urging North Korea "to cease its arms negotiations with Russia and abide by the public commitments that Pyongyang has made to not provide or sell arms to Russia".
It comes after Mr Shoigu also said on Monday that Russia and North Korea may hold joint war games.
"Why not, these are our neighbours," Russia's Interfax news agency quoted Mr Shoigu as saying.
"There's an old Russian saying: 'You don't choose your neighbours, and it's better to live with your neighbours in peace and harmony'."
When asked about the possibility of joint exercises between the two countries, he said they were "of course" being discussed, the agency said.
North Korea has previously denied having any "arms dealings" with Russia, however, the US has imposed sanctions on three entities it accused of being tied to arms deals between the two countries.
The White House also said last week that it had intelligence indicating that Mr Putin and Mr Kim swapped letters following Mr Shoigu's visit.
National Security Council spokesman John Kirby said the letters were "more at the surface level" but that Russian and North Korean talks on a weapons sale were advancing.
Mr Kim and Mr Putin previously met in Russia during a visit to Vladivostok in 2019, while Mr Shoigu visited the North Korean leader in Pyongyang in July for the 70th anniversary of the end of the Korean War - celebrated in North Korea as "Victory Day".
According to the New York Times, which first reported on the possibility of a meeting between Mr Putin and Mr Kim, North Korea could look for advanced technology to support its satellite and nuclear submarine programmes in return for artillery shells and anti-tank missiles.