Vladimir Putin’s army has lost more than 3,000 tanks during his invasion of Ukraine which is set to enter its third year, say British defence experts.
The huge destruction of these armoured military vehicles is equivalent to Russia’s entire pre-war active inventory, they added.
But they stressed that Moscow has enough lower-quality armoured vehicles in storage for years of replacements.
Ukraine has also suffered heavy losses since the invasion began in February 2022, but Western military replenishments have allowed it to maintain inventories while upgrading quality, the London-based International Institute for Strategic Studies said in its annual Military Balance report.
"Moscow has been able to trade quality for quantity though, by pulling thousands of older tanks out of storage at a rate that may, at times, have reached 90 tanks per month," said the major report, a key reference tool for defence analysts.
Russia's stored inventories mean Moscow "could potentially sustain around three more years of heavy losses and replenish tanks from stocks, even if at lower-technical standard, irrespective of its ability to produce new equipment," the report said.
Russia has an active force of 1,750 main battle tanks, ranging from decades-old T-55s to its modern T-80s and T-90s, the Military Balance said.
It has a further 4,000 in storage.
"The situation underscored a growing feeling of a stalemate in the fighting that may persist through 2024," the Military Balance said.
Russia's defence ministry declined to comment.
But Singapore-based defence analyst Alexander Neill, referring to the estimate of 3,000 tanks lost, said: "It's an astounding figure.
"Some of those could have been older tanks, so one of the big questions is how many of its most advanced tanks does it have left for any major future offensives," added Mr Neill, an adjunct fellow at Hawaii's Pacific Forum think-tank.
Hundreds of thousands of Russian and Ukrainian soldiers have also been killed or wounded, with the civilian death toll from Putin’s war having also risen above 10,000.
The US Senate is poised to pass a further military aid bill for Ukraine this week.
Britain has led the world in agreeing to arm Ukraine, first with anti-tank NLAW weapons, then Challenger II tanks and also long-range artillery.
With the conflict about to enter its third year, Ukraine's commanders have signalled they are prepared to keep grinding down Russia's forces across a 600-mile front, though Putin’s forces are making limited advances in some areas.
In an interview in January, Ukraine’s then-ground forces commander Oleksandr Syrskyi said defence remained the priority even as he did not rule out further offensive operations.
"Our goals remain unchanged: holding our positions... exhausting the enemy by inflicting maximum losses," said Syrskyi, who last week replaced Valeriy Zaluzhnyi, the popular leader of Ukraine's forces through the darkest days of the invasion.
Some analysts said the situation could test the ability of Russia's vast arms industry to produce new tanks and other weapons amid Western sanctions.
The Military Balance noted Russian industry executives had boasted of surging military production, while Russian officials have noted plans to resume production of its T-80 tank.
More broadly, the report noted that global defence spending is up nine per cent from 2022 and is poised to rise further in 2024.