As the Russian military launched its offensive on the eastern Ukrainian city of Avdiivka last fall, Ukrainian troops noticed a change in their tactics as column after column of Russian forces were ravaged by artillery fire.

Russian forces divided their infantry formations into smaller units to avoid being shelled, while the amount of Russian airstrikes increased to hammer the city’s defences.

It was one of several adjustments the Russians made to help reverse their fortunes after a disastrous first year. But these changes were obscured by one glaring fact: The Russian military was still far more willing to absorb big losses in troops and equipment, even to make small gains.

Russian forces have a different threshold of pain, one senior Western official said this month, as well as an unorthodox view of what is considered an acceptable level of military losses.

Hundreds of thousands of both Ukrainian and Russian soldiers have been wounded or killed since the start of Russia’s full-scale invasion, including tens of thousands last year in the battle for the eastern city of Bakhmut. Another town to the south, Marinka, fell to Russia in January, after heavy fighting and more losses.

Avdiivka was among the most costly. The various Russian casualty estimates circulating among military analysts, pro-Russian bloggers and Ukrainian officials suggest that Moscow lost more troops taking Avdiivka than it did in 10 years of fighting in Afghanistan in the 1980s.

But casualty numbers are difficult to verify – inflated by the side inflicting casualties and downplayed by the side suffering them – leaving the true cost unknown. The official figure of Soviet dead in Afghanistan, around 15,000, is considered to be significantly understated.

One prominent military blogger wrote that the Russians had lost 16,000 troops at Avdiivka, a number that for now remains impossible to confirm.

Mr Rob Lee, a senior fellow with the Foreign Policy Research Institute, which is based in Philadelphia, said: “Despite Russia’s heavy losses in Avdiivka, they still have a manpower advantage along the front and can continue assaults in multiple directions.”

Russia’s slow grind forward comes as European nations move to bolster support for Ukraine and strengthen their own protections against potential Russian aggression.

On Feb 26, Nato cleared the final hurdle for approving Sweden’s membership, less than a year after Finland joined, an expansion of the military alliance that defies the hopes of President Vladimir Putin of Russia of fracturing the unity of his adversaries.

President Volodymyr Zelensky of Ukraine said on Feb 25 that 31,000 Ukrainian soldiers had died fighting Russia. His comments drew notice for how rare they were; participants in war hardly ever reveal casualty numbers. But most Western analysts and officials say the toll is far higher.

Since the start of the invasion, Russia has been willing to pay a particularly high cost to advance in the area of eastern Ukraine known as the Donbas, where Avdiivka is.

Parts of this traditionally Russian-speaking region have been occupied by Russia’s proxies since 2014, and in trying to justify the full-scale invasion, the Kremlin has spuriously claimed to be defending its Russian speakers, saying they want to be part of Russia.

Some military analysts say taking full control of the Donbas is the bare minimum the Russian government needs to present the invasion of Ukraine as a victory at home. That perhaps explains Moscow’s willingness to absorb huge losses to make marginal advances.

Avdiivka has been strategic as well as symbolic for Russian war propaganda because of its proximity to Donetsk, the Donbas’ largest city, which has been under the Russian-backed occupation since 2014. Securing Avdiivka would move Ukrainian artillery away from the city, reducing civilian casualties and pressure on rear supply lines.

The Kremlin’s propensity to fire more shells, mass more people and lean on a much larger and capable air force in this war allowed it to gradually turn the tide against Ukraine’s deep defences in Avdiivka.

The huge cost in wounded and dead, some analysts say, was just the byproduct of a strategy that largely achieved its goal, despite the loss of men and materiel, especially as Western military aid and Ukrainian ammunition subsequently dwindled.

At least for now.

A Russian military analyst close to the defense industry, Mr Ruslan Pukhov, wrote last week that the assault on Avdiivka was part of a wider Russian strategy of pressuring Ukrainian forces along the entire 960km front line with thrusts and probes to exhaust the enemy “by a thousand cuts”.

“Such a strategy, however, is quite costly for the Russian Armed Forces in terms of losses, which could lead to depletion of its forces,” Mr Pukhov wrote in a Russian current affairs magazine. “This, in turn, could give the Ukrainian side the initiative once again.”

Most analysts, however, are issuing sobering assessments of Ukraine’s prospects for 2024 if it does not receive US aid.

As the war enters its third year, both sides are struggling to find enough men to continue fighting at the same level of intensity. Russia’s much larger population, about 144 million, which is three times that of Ukraine, gives it a significant edge in manpower.

The scale of Russia’s losses has partly negated the impact of this arithmetic.

The Kremlin’s decision to call up 300,000 men in September 2022 – for the first time since World War II – has shocked and unnerved the nation, according to polls. Hundreds of thousands of men had already fled the country when the war began, threatening to shatter the image of normalcy cultivated by Mr Putin.

Since then, the government has tried to postpone another round of mobilisation for as long as possible. Instead, it has boosted financial and legal incentives to attract convicts, debtors, migrants and other vulnerable social groups to the front as volunteers. It has also begun to strictly enforce the country’s previously lax mandatory military service for young men.

In a post published on the Telegram messaging app on Feb 18, a pro-war Russian military blogger cited an anonymous military source claiming that since October, Russian forces had sustained 16,000 “irreplaceable” human losses as well as that of 300 armoured vehicles in the assault on Avdiivka.

The Ukrainian forces had sustained 5,000 to 7,000 irreplaceable human losses in the battle, the blogger, Mr Andrei Morozov, wrote.

These claims could not be independently verified. NYTIMES