Ukraine military chiefs need to start planning for a breakout from Kyiv to establish a supply corridor to prevent thousands of deaths, leading analysts have said.
If Russia surrounds the capital and other major cities, the military and humanitarian situation will rapidly deteriorate unless food and ammunition can get through.
Analysts also say that the Russian offensive will become more violent after Moscow suffered setbacks that have caused them to lose between 4,000 and 6,000 troops.
“The Russians potentially have lost in just one week as many as the Americans did in the Iraq war from 2003 to 2010,” said Ed Arnold, a leading military analyst at the Rusi think tank.
The Ukrainian military will now have to prepare for more brutal tactics in Kyiv and other major cities as Russia attempts to strangle the country in submission.
Retired Brig Ben Barry argues that the best way to avoid catastrophe is to keep the Russians at bay.
“You ultimately want to avoid being surrounded so you have to fight and contest the efforts of the attackers to encircle you which means the Ukrainians have to fight them in the countryside,” said the senior fellow for land warfare at the IISS think tank.
The key to holding off the Russians is the continued resupply of military hardware to Ukraine. It is understood that large volumes of anti-tank and anti-aircraft missiles are being sent to major hubs in Poland before being driven overnight to Kyiv and other cities for distribution.
“This is continuous, although it’s a significant challenge to get in, especially so if the Belarusians attack directly south, putting a block on the main supply route,” said Mr Arnold.
If the Russians do encircle Kyiv — and with a 64-kilometre-long armoured column sitting nearby, they may well do so — Moscow’s commanders will be presented with their own difficulties, argued Mr Arnold, a former British Army infantry officer who served in Afghanistan.
“If the Russians move to assault quickly, they will get bogged down as fighting house-to-house in built-up areas is a nightmare, with the odds overwhelmingly favouring the defender,” he said.
“That said, the Ukrainians are running out of ammunition that can only be supplied overland, so if Kyiv is cut off, there needs to be a counter-attack to open a corridor to get the lethal aid and food supplies in.”
Weapons such as the British-supplied New Light Anti-tank Weapon and US-made Stinger anti-aircraft missiles will be key.
“Most of the Russian forces attacking Ukraine are in armoured vehicles, so these weapons are a very high priority,” said Brig Barry.
“All shoulder-controlled weapons, whether they're old-style RPGs or modern anti-tank weapons, are vital but there’s also small-arms ammunition, fuel and spare parts as well as non-lethal stuff, like helmets and body armour, and medical supplies, sleeping bags and compasses that they need.”
Once Kyiv is encircled the Russians will have two options. They can “strangle” the population through starvation and force them to capitulate, but Mr Arnold says that while it is less intensive in terms of casualties, “it takes a lot of time".
Alternatively, they can be more aggressive and mount a major offensive.
“Russia has performed so badly that they'll want quick wins to get a bit of tempo into their operations,” he said. The Ukrainians will also have to prioritise the areas they want to defend “because they just don't have the manpower everywhere”.
Either way, the number of civilian casualties could reach the “thousands a week and could pretty quickly get out of hand”, Mr Arnold added.
As they showed in Syria, the Russians have no compunction in using artillery and aerial bombardment to subdue a city, while potentially offering safe passage out for both civilians and fighters.
“They will also continue to attempt to strike the military and political leadership in the city, by mounting raids or limited ground attacks to gradually wrest control from the defending forces,” said Brig Barry.
Pictures of Russian atrocities against civilians could lead to intensified calls for no-fly zones or “safe zones” within Ukraine free from any military action.
But if the military supplies continue to arrive, Ukraine’s forces could potentially hold off the Russian advance — something nearly all experts considered impossible a week ago.
“I was surprised by the success of the Ukrainian forces and maybe I'd underestimated them and overestimated the standard training and leadership of the Russian forces that seemed to perform pretty successfully in Syria,” said Brig Barry.
“But of course, in Syria, they didn't actually introduce any Battalion Tactical Groups or brigades to go toe-to-toe with the Syrian rebels or ISIS.”
Analysts also highlight the generation of battle-hardened combat leaders that have come through seven years of fighting Russia-backed forces in eastern Ukraine.
The defenders also have the “moral component” of fighting for their homeland against a foreign invader, enhanced by the leadership of Ukrainian President Volodymyr Zelenskyy.
In contrast, the Russians have shown poor leadership and planning, said Mr Arnold.
“The Russian war machine has just completely misfired in the opening stages of the war and I think that's down to a failure of political and military leadership,” he said.
“There are lots of reports suggesting the Russian troops didn't actually know what they were up to until the 11th hour.”
Brig Barry suggests that Moscow’s generals prioritised combat forces over logistics in the hope of a quick win, assembling 150,000 troops for the invasion but without the supplies to keep them in the field.
Could that mean the Russians might actually be defeated in battle?
“There’s a chance of that but there's also a chance the Russians could escalate even further,” he said.
“So it’s quite finely balanced and we might only be in the first 15 minutes of the first half of this war.
“Who knows what comes next?”