Ros Atkins On... Are North Korean troops fighting in Ukraine?

As the Russian defence minister makes an unannounced visit to Pyongyang and Ukraine claims that North Korean troops are in Russia and ready to support Russia's military - our Analysis Editor Ros Atkins, along with BBC Verify, has been looking at what we know about North Korea's alleged involvement in the war.

Produced by Catherine Karelli, Richard Irvine-Brown, Vitaly Shevchenko, Olga Robinson and Jake Kwon.