A seventh Russian general has been killed in Ukraine, according to western officials who claimed on Friday another senior commander was targetted by his own troops in Ukraine.
The alleged losses came as Russia scrambled to replenish its depleted ranks following a string of military setbacks.
Nato estimates that between 7,000 and 15,000 Russian troops have been killed in the month-long conflict. Up to 20 of the estimated 115 battalion tactical groups that despatched to Ukraine a month ago are now “combat ineffective”, security officials said. Some legacy units have been forced to amalgamate to create operational forces.
The list of killed senior commanders has been growing over the past two weeks, with it being suggested that western intelligence is assisting Ukraine’s military in helping it find and eliminate officers.
On Friday, it was confirmed that battle-hardened Syria veteran Lt Gen Yakov Rezantsev, commander of the 49th Combined Arms Army, had been killed.
When promoted to his new post, Rezantsev, 48, was described by his commanders as an “experienced combat officer who successfully performed special tasks in Syria”.
His death means that a remarkable 35 per cent of Russia's 20 operational generals deployed to Ukraine have been killed in combat.
That number grew further on Friday when it was reported that a colonel in charge of the 37th Guards Motorised Rifle Brigade had been attacked by his own soldiers.
“We believe he was killed by his own troops deliberately as a consequence of the scale of losses that had been taken by his brigade,” a western security official told the media.
“That gives an insight into some of the morale challenges that Russian forces are having.”
The official suggested there had been “really high losses in some motor rifle regiments”, meaning that 20 of the battalion tactical groups “are no longer combat effective”.
Most units, numbering 800 to 1,000 men, were reportedly either being pulled back to Russia for repairs or reinforcements but the casualties among some were so high that they virtually disappeared.
“They have just lost enormous numbers of people so that what we've seen is the cannibalising of battalion tactical groups, joining three together to create one,” the official said.
“A fifth of the force being no longer combat effective is a pretty remarkable sets of statistics.”
Moscow has been rapidly attempting to generate new battalion tactical groups, taking troops from the Eastern Military District, Georgia and Kaliningrad.
The soldiers were being rushed into battle, potentially unprepared and ill-equipped, the official said.
“If they're brought into the fight quickly then they'll go from being in barracks to being in significant combat in a pretty short space of time,” he said.
“Therefore, there is a question over how effective and how prepared they are for those operations.”
Russia has almost 10,000 troops in occupied territories of Georgia and across military bases in Abkhazia and South Ossetia.
A senior US defence official said Russia was looking to utilise an unspecified number of those forces.
"We now have signs that they are drawing upon troops, Russian troops, that are based in Georgia,” the official told Pentagon reporters.
With Ukrainian forces pushing back the Russian invaders by up to 35 kilometres beyond Kyiv and retaking some towns, the ability of Russia to continue its broad offensive is in question.
The US official said Moscow is temporarily abandoning a ground assault on Kyiv and focusing on the Donbas region in the east.
“It appears that the Russians are are at the moment not pursuing a ground offensive towards Kyiv. They are digging in there, establishing defensive positions," the official said.
"Clearly they overestimated their ability to take Kyiv."