Russian forces withdraw from key eastern towns.

Ukrainian officials say troops have entered Kupiansk, a vital eastern supply hub for Russian forces.

In an extra episode of Ukrainecast, Vitaly and Victoria discuss the significance of the Ukrainian gains and analyse the Russian reaction. The Ukrainian advances - if held - would be the most significant since Russia withdrew from areas around Kyiv in April.

Ukrainecast was made by Sam Bonham. The Senior News Editor is Jonathan Aspinwall.