Mariupol is under siege, Kherson has been captured and Ukrainian forces are preparing for a Russian assault to seize Odessa.
The battle for Ukraine has become a battle for its large cities. Yet the big strategic prize, the one Russian president Vladimir Putin imagined would be achieved quickly, remains Kyiv.
The lightning capture of the capital, compelling Ukrainian president Volodymyr Zelenskiy's government to surrender, was a strategic objective when Russia launched its invasion last month.
Russian forces have so far advanced into the suburbs of Kyiv and the city has been subject to heavy shelling – eight people were reportedly killed as a result of a strike on a shopping mall on Sunday evening.
But Moscow’s plan to take the capital has been frustrated by its own miscalculations and the spirited ability of those defending the city to resist, harass and counter-attack.
"Kyiv is still the main objective and that is clear . . . for both sides," said an intelligence official with the Nato military alliance. "Clear in terms of what the Russians have said their desired end-state is, and what the Ukrainians know they must defend at all costs."
Fierce battles in the city's suburbs, see-saw fighting for control of the key airfield at Hostomel, and solid Ukrainian air defence systems prevented a repeat of the US "thunder run" to capture the Iraqi capital Baghdad in 2003. The bulk of Russian forces remain more than 25km from the centre of Kyiv, the UK Ministry of Defence said on Monday.
Even so, that puts the capital in range of the same kind of indiscriminate artillery barrages that the Russians have unleashed on the southern city of Mariupol and Kharkiv in the east. These tactics were used in 1995 to flatten the Chechen capital Grozny and during Russia's campaign in Syria this century.
"Urban warfare is incredibly tough and for attacking forces that means giving it all you've got," said John Spencer, a former US army major and now chair of urban warfare studies at the Madison Policy Forum think-tank. "What Russia has got a lot of is artillery – as Stalin said, 'quantity has a quality of its own'."
One such “quality” is the consequences such heavy shelling wreaks on a civilian population. “Attending to those humanitarian needs sucks up a lot of effort and manpower of the Ukrainian forces,” Spencer said.
It remains uncertain whether Russian forces can encircle Kyiv and force it to succumb. Its forces have been held at bay to the north and north-east of the capital for several weeks, although the giant convoy that arrived in the north-west has begun to fan out.
Kyiv’s geography and topography also makes it a difficult city to take – it is hilly, partly wooded and bisected by the Dnieper river.
Even if Moscow does launch a full-on attack, western defence officials and analysts concur that its forces are insufficient to take and hold Kyiv.
The conventional wisdom is that an attacking force requires five soldiers for each person defending, "but in many conflicts it has been more like 10:1," said Anthony King, chair of war studies at the UK's University of Warwick. "So even if you assume there are just 10,000 organised Ukrainian fighters in Kyiv, that implies a Russian force of perhaps 100,000."
Yet “because Russia lacks those forces, that makes it more likely they will turn to heavy bombardment instead”, he said.
During the 1995 Grozny siege, Russian artillery fired 30,000 rounds a day at its peak, equivalent to one every 20 seconds, according to Spencer, leaving an estimated 27,000-50,000 civilians dead out of the city’s original population of 270,000.
This was “where the cruel math of a conventional war is brought to bear”, the Nato official said. “The Russians have deeper potential for resupply than the Ukrainians do.”
Unlike Grozny, though, Kyiv has an extensive underground metro system, with more than 60km of tunnels that have already been used to shelter civilians. The Arsenalna metro station in central Kyiv is the world’s deepest subway, lying 105m below its entrance.
“These subways give the defender the ability to survive, and to survive a long time, like in the London Blitz,” said Spencer, who has detailed how the battle for Kyiv might play out in a recent podcast. “It even emboldens them [the defenders] that they survive.”
Given how well Kyiv is defended and the depletion of Russia’s own resources, analysts said Moscow may decide against an assault on the city if it can achieve strategic goals elsewhere – such as consolidating a land bridge between the occupied Crimea peninsula and the eastern Donbas region.
It could then use artillery bombardment and the threat of a massive attack on Kyiv to pressure the Zelensky government to come to terms.
There are already indications of a change in Russia’s strategy in anticipation of a longer battle, with satellite images suggesting that its forces are digging in north-west of the city.
"[Russia] may see [besieging Kyiv] as an opportunity to deplete the Ukrainian manoeuvre forces, to use Kyiv as a base to continuously lure Ukrainian armour into battle," said Gustav Gressel, a military analyst at the European Council on Foreign Relations, and a former Austrian defence official.
But that approach also carries considerable risks for Putin given that sieges typically take a long time and Russian troop losses continue to mount.
Conventional strategy also says urban sieges are best undertaken when the surrounding territory has been safely secured. This is far from the case in Ukraine, where insurgents continue to lead successful counter-attacks on Russian troops.
“Ukraine does not need to destroy the Russian army to win,” Spencer said. “It just needs to hold terrain.” – Copyright The Financial Times Limited 2022