The traditionally Russian-speaking area is at the heart of what the Russian president calls the “root causes” of the war, and taking it over is near the top of his list of territorial and political demands.

President Donald Trump supports Russian leader Vladimir Putin's proposal for Moscow to take full control of the Donbas and freeze the front lines elsewhere for a deal with Ukraine.

The Donbas, comprising Luhansk and Donetsk with a pre-war population of 6.5 million, has been at the centre of fighting since Russia’s 2014 annexation attempts. Moscow currently controls nearly all of Luhansk and around 70% of Donetsk.