A major turning point in the Ukraine war could be under way at Kherson, a southern Oblast — or administrative region — that is home to the city of the same name, one of Ukraine's largest cities under Russian occupation.
On Tuesday, Russia's most senior commander in the Ukraine war, Sergey Surovikin, told reporters in Moscow that Russia was preparing to make "difficult" decisions in the southern city, which led to speculation that his forces might evacuate the area.
Is Ukraine taking back Kherson?
The possibility that Russian forces could be quickly pushed out of Kherson gained traction on Tuesday when the Russian-installed administrator Vladimir Saldo urged an evacuation of 60,000 civilians.
Ukrainian operations in the area began on August 30, cutting through a line of Russian defences — while Russia said Ukrainian forces suffered heavy casualties. This initial attack appeared to distract Russian forces, who moved troops from Kharkiv in the north to reinforce Kherson.
Ukraine then launched a surprise offensive in the Kharkiv area, routing Russian troops and retaking swathes of territory.
Now the focus has shifted back to Kherson. If it can be retaken, it could mark a turning point in the conflict, putting Ukrainian forces within reach of Russian-occupied Crimea.
The city is sometimes called the “gateway to Crimea". With a pre-war population of about 300,000, it is cut off from the bulk of Russian forces by the wide, 2,200-kilometre long Dnipro river, as well as a series of smaller rivers and lakes to its south.
This has allowed Ukrainian forces to move towards the city, pinning an estimated 20,000 Russian forces up against the river behind it.
The battle for Kherson
As per an analysis by Jack Watling of the UK’s Royal United Services Institute, some of Russia’s best airborne units are in and around the city.
Two major bridges that could resupply the considerable Russian force on the northern bank of the river have been gradually damaged by US-supplied Himars missiles and are now unusable for armoured vehicles and other heavy supplies.
This has potentially created an opportunity for advancing Ukrainian forces — if the Russians cannot resupply, they may be forced to evacuate the city.
Constant resupply can represent the difference between victory and defeat. French forces suffered a humiliating defeat at Dien Bien Phu in Vietnam fighting Communist insurgents in 1954, when they could not be adequately resupplied.
British paratroopers also suffered disaster at Arnhem in the Netherlands in the Second World War, cut off from nearby US and British reinforcements who were struggling to take river crossings from the Germans.
The British paratroopers eventually gave in to a superior German force when they ran out of ammunition.
Analysts say such an outcome in Kherson is far from certain, despite Russian supply requirements of about 200 kilograms a day, per soldier. This amount is a representative figure that includes all logistical support including food, medicine, ammunition water and items such as radio batteries.
John Curry, an expert on warfare at Bath Spa University, said this could add up to 1,300 tonnes a day per brigade of 3,000 men in sustained combat.
Without adequate bridges, moving these supplies will be a considerable feat.
But Ukraine also has problems, analysts warn. This include logistical challenges such as the co-ordination of foreign arms supplies for a vast array of different weapon systems, a process co-ordinated by the US at their European military headquarters, in an office known as the International Donor Co-ordination Centre.
By contrast, Russia's military hardware, manufactured domestically, does not suffer this compatibility challenge of ammunition and parts.
Many Ukrainian units have also suffered exhaustion from months of combat against an enemy that has been able to deploy greater numbers of armoured vehicles and field artillery pieces, having taken heavy casualties over the summer, up to 200 a day.
While Russian losses have also been heavy, analysts often say that offensive actions require higher numbers of men than defending forces — another challenge where the burden is on Ukraine.
Both sides are short on the manpower needed to fight across vast expanses of terrain, which was contested by millions of opposing soldiers between 1941 and 1944, when the Nazis were pushed out of Ukraine by the Soviets.
Why does Kherson matter?
Russia has tried to annex Kherson, where about 25 per cent of the population speak Russian. Vladimir Putin said on September 30 that a referendum on the issue — widely rejected by 143 UN member states as a fake poll, had been successful.
Analysts have warned that the outcome of Ukraine’s third major counteroffensive of the war could influence the level of Western support for the country, as Russia continues to withhold gas supplies to Europe.
If Ukraine cannot take the city and surrounding Oblast, it could create a sense among Western allies that the war has reached a stalemate, and that a political solution should be pursued.
Conversely, if the Ukrainians succeed in pushing Russian forces out of the city, it could result in a political boost for the government in Kyiv and help to guarantee further Western support.