A former British Army officer says resupply problems for the Russians could ultimately help Ukraine win back the southern port city of Kherson.
Can Ukrainian forces retake it without destroying it?
It is the only regional capital that Russia has been able to capture from Ukraine since it invaded more than six months ago.
Ukraine's military has begun a counter-offensive against Russian forces in the country's south, according to its southern command.
Colonel (Ret'd) Tim Collins told Forces News: "The intention, I suspect, in Kherson, is a) to liberate the city as intact as it can possibly be, but also to fix the Russian garrison, which is inside the city, to a great extent, because that's the Russians' vulnerability.
"They have a garrison in the city which is, to a large extent, cut off from its supply lines, because of the Dnipro River. The likelihood is that, when encircled, that garrison will have to surrender.
"That would be an optimal, an ideal situation for the Ukrainians, but even if that doesn't happen, what it does is it fixes Russian troops in that area."
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Colonel Collins stressed the importance of balancing the need to retake the city with the protection of its people.
"One thing that's not on the agenda is destroying Kherson itself," he said.
"The thing you have to balance is that, whilst starving the garrison, the Russian garrison is one thing – you're also starving the people of Kherson at the same time, so there's a balance to be struck there.
"I think that the opportunity to so beleaguer the Russian garrison that they run out of ammunition and they run out resupply and petrol and everything else they need to the point where they have to surrender is probably a good way of a) ensuring that the Russians aren't up to any mischief elsewhere because their whole focus is going to have to be on supplying this garrison, much in the way that the Germans in the Second World War found themselves fixed with the Siege of Stalingrad.
"They had to keep resupplying, they couldn't keep resupplying Stalingrad and that was ultimately what led to their defeat. I think that's going to be the case in Kherson as well."
Ukraine has continued to make progress in advancing the frontline in some places, according to Defence Intelligence, the Government's information analysts.
Kherson, a city key due to its access to the sea, was captured by the Russians in early March, not long into the invasion.