According to the assessment of a nation in the Group of Seven, China is unlikely to be pleased with the alliance between Russia and North Korea, the people said. The upcoming G-20 summit in Rio will be an opportunity to push the issue with Beijing, said the people, without providing more specifics.

The U.S. says there will be a "firm response" as Ukrainian forces holding ground in Russia's Kursk region now face North Korean troops "engaging in combat."

Russia attacked the Ukrainian capital Kyiv with a sophisticated combination of missiles and drones for the first time in 73 days on Wednesday, authorities reported, as the Pentagon said most of the North Korean troops sent to help Moscow’s war effort are fighting to drive Ukraine’s army off Russian soil in the Kursk border region.