The possibility has alarmed leaders and deepened diplomatic tensions.
The hordes of men could be gearing up to storm the frontline after the US confirmed that at least 3,000 of Kim Jong Un's troops had entered Russian territory.
More videos posted on social media and satellite imagery suggest that North Korean soldiers are at Russia's military training sites for possible deployment in the war in Ukraine, The Washington Post has reported.
South Korea has expressed “grave concern” over Russia’s bid to seal a defence pact with North Korea, which has been accused of supplying troops to Moscow for possible deployment in its war in Ukraine.
