Vladimir Putin will have to sacrifice between 500,000 and one million men if he wants to seize all of the Donbas region of Ukraine, according to a top military analyst.
Professor Michael Clarke believes Russia has already suffered more than one million casualties – that is, dead and seriously injured – since the war began in February 2022. Russia currently occupies around 20 per cent of Ukraine.
Russian President Putin has altered his aims since Russia’s full-scale invasion, saying that securing the Donbas is now his main priority. It is thought Russian forces currently control at least 90 per cent of the resource-rich region, which is made up of the Donetsk and Luhansk regions.
The Institute for the Study of War estimated in October 2025 that Ukraine still holds around 6,500 square kilometres of territory in Donetsk – equivalent to a quarter of the region. Crucially, it includes a belt of ‘fortress cities’ including Kostiantynivka, Kramatorsk, Druzhkivka, and Sloviansk.
Russia has also sustained horrific casualties as it wrestles for control of the city of Pokrovsk, and Prof Clarke explained to Sky News that it could expect many more casualties if it hoped to capture the entirety of the Donbas.
“If the Russians continue this grinding offensive and if they are prepared to take another half a million or a million casualties by, let’s say, September next year then they probably get the Donbas,” he said.
“That’s how I would assess where the war is at the moment. They are already at over a million now.
“By casualties, we should say that means dead and wounded – and by wounded, we mean life-changing injuries, injuries that take you away from the battlefield – not wounds that mean you have to go to hospital then back to the battlefield in a month.
“A lot of wounds are like that, but these are wounds that take you off the table, so to speak, as a fighter.
“The casualties are at significantly over a million now for Russia and about, we think 300,000-400,000 for Ukraine.”
It is also thought that Moscow controls pockets of territory along the Russian border with Ukraine’s Sumy and Kharkiv regions. It has also captured some of Kharkiv after pushing forces west from Luhansk. The Kremlin has also seized very small areas of the southern Mykolaiv region and of Dnipropetrovsk, which borders Donetsk.
However, there are still areas to be positive for Ukraine, Prof Clarke explained: “The war is at a stalemate in one respect and dynamic in another. The Ukrainians are doing well in the Black Sea, they are doing quite well economically, and they can probably get through this winter.
“It is going to be really tough for them but they have more independent generating capacity – literally, lots of generators. They are linking themselves into the west European energy grid relatively successfully, so they will probably be able to get through.”
“We are also heading into winter,” he continued. “In general, winter favours defence over attack. If you are on the defensive, you are dug in wherever you are and you don’t have to move, you just have to hold your ground.
“If you are on the attack, you have to move. You are moving forward, you are establishing new positions, so the ground is harder to work on and dig in.”
