Twenty thousand of Russia’s most capable troops face being surrounded and defeated if Moscow’s generals do not order their withdrawal, western officials said on Friday.
The mobilisation of 300,000 reservists by President Vladimir Putin to prevent further Ukrainian gains had led Russia to call in troops of “very low quality”, officials told a media briefing.
The Kremlin’s threat of nuclear retaliation if Ukraine crosses “red lines” by entering territory now claimed by Russia after “sham referendums” are understood to be hollow, the officials said.
The counter-offensive in the strategically important port of Kherson, the only city to be seized by the Russians in their seven-month campaign, has been under way since August.
Using western-supplied long range artillery, Ukraine has been able to cut-off the Russian occupiers, that include airborne troops, on the western bank of the 1,000-metre wide Dnipro river.
However, this month's defeat in the Kharkiv region, with Ukraine seizing back territory the size of Cyprus, Moscow would be extremely unwilling to order a withdrawal.
“We assess that Russian commanders will now consider the roughly 20,000 force on the West Bank to be extremely vulnerable and withdrawal from that ground would make operational sense,” one official said. “But the area clearly has political significance and it's the only regional capital that Putin has seized since the start of the invasion.”
The Ukrainian advance has been incremental around Kherson, mainly focusing on destroying Russian supplies including large artillery stockpiles and bridges.
Asked by The National if a Ukrainian breakthrough could lead to a sudden collapse with a swift push on Crimea 90 kilometres away, the official said Russia had “defence in depth” beyond the Dnipro’s eastern bank, making a break-out difficult.
“But one of the challenges in assessing this is the morale factor because these things are a genuinely hard to assess and you can't rule it out,” the official said.
With the loss of territory in the north-eastern Kharkiv region and the pressure on Kherson in the south, Mr Putin has called up a raft of reserves to make up for the losses of 80,000 troops either killed, severely wounded or deserted.
But the call up is causing disquiet in Russia and the troops are said to be poorly trained and equipped, with some in their 60s.
“Russian military planners will face a dilemma of either very low-quality reinforcements soon or a better-trained force later,” the source said. “Russia has effectively exhausted the pool of willing volunteers for combat duty and Ukraine.”
“Russian forces have been largely fixed, trying to hold a line effectively across an area the size of Great Britain with very few reserves of any quality."
Despite the partial mobilisation Mr Putin, still has no plans to admit that Ukraine is a war rather than what he has called a “special military operation”.
But the contradiction, with more men being forced on to the front line, was creating a “dissonance in Russian society” and this was “likely to certainly increase”.
The mobilisation was unlikely to include sons from “well-off families” and there was increasingly “shallow support for the war across Russian society”.
The current referendum in Donbas, which is highly likely to be fraudulent, is partly to produce red lines with a nuclear threat. However, officials believe that the Kremlin’s red lines “are not probably in exactly the places where they say they are”.
“These statements are made with intent and the intent is to deter, it doesn't necessarily reflect the true calculus of the Kremlin,” the official said.
However, Ukraine’s gains in Kharkiv, and potentially Kherson, were “politically significant and have caused extreme concern in the Kremlin and elsewhere in Moscow”.