"We have new information that Russia is actively seeking to acquire additional munitions from North Korea," White House national security spokesman John Kirby said.

He said the man, identified as Ashot Mkrtychev, 56, of Bratislava, was working on arms-related sales and barter deals between the two countries between late 2002 and the early part of this year.

"With the support of Russian officials, Mkrtychev has been attempting to broker a secret arms agreement between Russia and North Korea," he said.

Under discussion was for North Korea to ship "over two dozen" kinds of weapons and munitions to Russia, according to the US Treasury, which placed Mkrtychev on its sanctions blacklist.

In exchange, the Treasury said, Pyongyang would obtain cash, commercial aircraft, commodities and raw materials.

Kirby said that the United States understands that Russia is seeking to send a delegation to North Korea and is offering Pyongyang food in exchange for munitions.

He did not say if any deals had been completed, or detail the specific weapons involved.

"Any arms deal between North Korea and Russia would directly violate a series of UN Security Council resolutions," Kirby said.

Kirby said the deals Mkrtychev was involved in were separate from North Korea's sale late last year of rockets and artillery munitions to the Wagner Group, a semi-independent Russian military force which is fighting on the front lines in Ukraine.

Being placed on the Treasury sanctions list cuts Mkrtychev off from the US financial system, according to Kirby.

"He will face significant challenges in attempting to access and abuse the international financial system now that his activities have been exposed," he said.

The blacklisting also places in jeopardy anyone who provides support to Mkrtychev, Kirby said.

"Today's action is a clear message that the United States will not relent in targeting those who provide support to Russia's aggression and brutal war against Ukraine," said US Secretary of State Antony Blinken.

"We will continue to identify, expose, and counter Russian attempts to acquire military equipment from (North Korea) or any other state that is prepared to support its war in Ukraine," Blinken said in a statement.