North Korea's Kim Jong Un plans to travel to Russia this month to meet President Vladimir Putin, a US official has told the BBC's US partner CBS.
The two leaders will discuss the possibility of North Korea providing Moscow with weapons to support its ongoing war in Ukraine, the official said.
The exact location of the planned meeting is not clear.
Mr Kim is likely to travel by armoured train, sources told the New York Times.
The possible meeting comes after the White House said it has new information that arms negotiations between the two countries are "actively advancing".
National Security Council spokesman John Kirby said that Russia's defence minister recently travelled to North Korea to "try to convince Pyongyang to sell artillery ammunition" to Russia.
Mr Putin and Mr Kim have since exchanged letters "pledging to increase their bilateral cooperation", he said.