The United States warned North Korea over its supreme leader Kim Jong Un's possible upcoming visit to Russia to discuss arms supply to Moscow for the ongoing war against Ukraine and said Pyongyang will pay a price for it.

US national security adviser Jake Sullivan told reporters at the White House: "Providing weapons to Russia for use on the battlefield to attack grain silos and the heating infrastructure of major cities as we head into winter to try to conquer territory that belongs to another sovereign nation — this is not going to reflect well on North Korea, and they will pay a price for this in the international community."

He said: "We have also imposed sanctions — specific, targeted sanctions to try to disrupt any effort to use North Korea as a conduit or as a source for weapons going to Russia."

"We did so as recently as mid-August. And we have continued to convey privately as well as publicly to the North Koreans — and asked allies and partners to do the same — our view that they should abide by their publicly stated commitments that they’re not going to provide these weapons," the top US official said.

He said: " But we will continue to look for opportunities to dissuade the North Koreans from taking this step, to get others to do the same, and to report to the world what we are seeing in terms of the actively advancing discussions that are taking place between these two countries."

A U.S. official earlier told CBS News that the North Korean leader will discuss the possibility of his nation supplying weapons to Moscow to support its war against Ukraine.

The possible meeting between the Russian and North Korean leaders comes after the White House said it had new information that arms negotiations between the two countries were 'actively advancing', CBS News reported.

National Security Council spokesman John Kirby told reporters on last Wednesday as quoted by CBS News that Russia's Defence Minister, Sergei Shoigu, recently travelled to North Korea to "try to convince Pyongyang to send artillery ammunition" to Russia, and after the visit, Putin and Kim exchanged letters "pledging to increase their bilateral cooperation."

The Russian government, however, declined to comment on Kim Jong Un's possible visit to the country.

“We have nothing to say on the subject,” Kremlin spokesman Dmitry Peskov said on Tuesday as quoted by CNN.