A chemical plant recently captured by Russian troops in the frontline town of Avdiivka in Donetsk region, eastern Ukraine, on February 20, 2024.
CNN  — 

A series of swift Russian advances have challenged Ukraine’s new line of defense set up after their withdrawal from the key town of Avdiivka and are raising fears about Kyiv’s tactics and momentum on the front lines.

Ukraine announced a withdrawal from Avdiivka on February 17 to a series of positions to the town’s west. Yet three tiny villages have since fallen to Russian forces, with Kyiv insisting they never intended to defend them.

But the defensive line it declared it would fall back to - three villages further to the west - has since come under heavy Russian assault, with pro-Russian sources claiming Moscow has partially occupied all three settlements. Ukraine denies the claims.

The Russian advances come in the face of a deep crisis in munitions for the Ukrainian military, creating a near-existential debate for frontline troops who must ration ammunition and are questioning how long they can withstand Russian pressure.

In another sign of the mounting sense of unease, the new commander of the Ukrainian military, Col. Gen. Oleksandr Syrskyi, twice in the past week scolded his subordinate officers for poor performance on this key front line.

On Thursday, Syrskyi criticised “certain shortcomings” and “miscalculations” by commanders on the Avdiivka front lines “which directly affected the sustainability of defence in certain areas.” On Saturday, he returned to the theme of inadequate staffing, suggesting he had replaced some officers who were “not aware of the situation” and “directly endanger[ed] the lives and health of [their] subordinates.”

Syrskyi became the military’s new commander three weeks ago, after his widely popular predecessor, Valery Zaluzhny, was replaced following months of tension with President Volodymyr Zelensky.

Syrskyi has inherited a battlefield where a resurgent Russia and brutal ferocity has exploited long-telegraphed shortcomings in Western aid, ammunition and personnel for Ukraine.

Col. Gen. Oleksandr Syrskyi attends a meeting in Kyiv on February 10, 2024.

Pessimism on the eastern front

The Russian assault of Ukraine’s new defensive line around Avdiivka is significant not because of the value of the tiny villages themselves - containing at best dozens of holdout residents and destroyed buildings - but because they suggest Ukrainian officials inadequately planned for the Avdiivka withdrawal and have since been unable to stem Russia’s advance.

Moscow has claimed its stated goal is the capture of the entire Donbas region, yet it also wants to “demilitarize” Ukraine.

Multiple Ukrainian soldiers expressed stark pessimism to CNN about the withdrawal’s significance and the later defense as a harbinger for the weeks ahead. Many asked not to be quoted discussing a sensitive matter.

One special forces soldier told CNN: “It’s not so much about [Russian] momentum, but more about us being badly prepared to hold them off. As long as we didn’t have good, prepared positions we keep rolling and rolling and rolling back.”

Another officer on a pressured front line said: “We can feel [Russian] superiority in personnel, artillery and armored vehicles. They move forward little by little. We have not many options here. Fall back, or just wait till we are… No matter how sad it may sound, till we are all killed. Without weapons… it’s not a war you can fight with a sword.”

Ukrainian casualties are usually shrouded in secrecy, despite President Zelensky saying last weekend 31,000 troops had died since the Russian invasion began. Yet in one trauma unit near the front line in the east, a concerned medic showed CNN a box of injury reports that numbered in the high hundreds from 20 days?in February alone.

Drone footage from the village of Orlivka, a focus of Russia’s ongoing assault to Avdiivka’s west, shows most buildings in ruins and vast craters likely from Russian airstrikes across the flat, riverside terrain. Fierce clashes have persisted around the other two villages near Avdiivka,? Tonenke and Berdychi. CNN heard intense explosions and heavy machine gunfire near Berdychi on Saturday.

Soldiers interviewed across the eastern front line also expressed grave pessimism about the coming spring if Western assistance was not urgently supplied. The combination of ebbing Ukrainian morale and supplies and Moscow’s forces appearing to gain momentum marks a pivotal moment in the conflict.

A Ukrainian soldier prepares a shell for a drone on the front line near Avdiivka on February 20, 2024.

Drone footage of Russian forces has repeatedly revealed a military unafraid of sending troops at speed into indefensible positions where they will likely be killed.

In footage reportedly from the Avdiivka region from Ukraine’s 47th Mechanized Brigade, a Russian armored personnel carrier races toward Ukrainian positions, and stops for seconds to discharge about a dozen soldiers who take cover in a nearby gateway.

Two Ukrainian attack drones disable the vehicle and a US-supplied Bradley armored vehicle approaches the exposed group. It is then seen shooting many of the Russians with a mounted grenade launcher.

Another video from outside the village of Berdychi shows more than 30 dead Russian soldiers behind a damaged armored vehicle. CNN was not able to verify the location of either video.

Yet despite the staggering casualties and unsophisticated tactics, the Russian assaults persist.