Russian forces committed a division to take several more villages in Ukraine’s east during the past week, as Ukraine’s European allies frantically increased their weapons pledges and the full effect of long-delayed US military aid became apparent.

Most of the Russian tactical gains came west of Avdiivka, which fell on February 17, and where the Russians have maintained their momentum.

Russian forces advanced into the northern reaches of the village of Semenivka last Wednesday, overran Novobakhmutivka five kilometres (3.1 miles) to the north and attacked neighbouring Solovyove. By Friday, Semenivka and Solovyove, too, had fallen. Russian forces on Saturday launched a massive assault on Ocheretyne, two kilometres further north, and had reached its western outskirts by Monday.

Lieutenant Colonel Nazar Voloshyn, spokesman for Ukraine’s Khortytsia group defending this area, said Russia had committed four brigades to the offensive, about 20,000 men, and that Ukrainian reserves had been sent in to bolster defences. Fierce battles for Ocheretyne continued on Tuesday, but the Russian advance had already created a five-kilometre-deep salient into Ukrainian free territory.

The Telegraph, a British newspaper, reported that Russia had attacked during a brigade-level rotation on the front lines.

While Russia focused on the Avdiivka area, its attacks lessened in the other area of intense conflict, Chasiv Yar, some 45km (28 miles) to the north, which Russian forces have been trying to capture as a gateway to the rest of Donetsk. But on Monday, they unleashed their fury here, too, focusing on two villages to the north and south of Chasiv Yar in a now familiar Russian attempt at operational encirclement.

“There were attempts by the enemy to bypass Chasiv Yar near the villages of Ivanivske and Bohdanivka. In this way, the enemy wants to take the city in a vice, go around it in a circle,” Voloshyn told a telethon, adding that all assaults had been repelled.

Bohdanivka was being still contested on Tuesday, but geolocated footage showed that Russian forces had mostly overtaken Ivanivske three weeks earlier, and on Tuesday struck west of the village to reach the Siversky Donets-Donbas canal, a mere kilometre (0.6 miles) south of Chasiv Yar. At that point, the canal runs underground and Ukrainian forces are deprived of a natural defensive feature.

“The situation at the front worsened,” announced Ukrainian commander-in-chief Oleksandr Syrskyii on Telegram on Sunday, explaining that Russian forces were trying to use the canal as a line of advance.

The Siverski Donets-Donbas canal runs hundreds of kilometres through Chasiv Yar and into north-central Ukraine.

Syrskyii said Russian forces were also trying to capture nearby Klishchiivka, which Ukrainian forces recaptured during their counteroffensive last September, and through which the canal also runs.

Casualty figures suggested the depth of Russian commitment to these goals.

On Sunday alone, Ukraine’s armed forces said they killed or wounded 1,320 Russian soldiers, and another 1,250 on Monday, but it was clear that the vast majority of these were on the Avdiivka and Chasiv Yar fronts.

Russia rarely comments on its losses, while Al Jazeera was unable to confirm the toll.

On Monday, Voloshyn said the Khortytsia group alone had “eliminated” an average of a thousand Russian soldiers a day in the previous week. Out of 131 combat clashes on Sunday, Ukraine’s General Staff said 55 had been west of Avdiivka.

However, Russia has shown that it has a high pain threshold for casualties.

The United Kingdom’s minister of state for the armed forces, Leo Docherty, said Russia had suffered an estimated 450,000 casualties during the full-scale war, and had lost 10,000 armoured vehicles, including 3,000 tanks.

In addition, a proportion of the Russian losses consists of low-quality troops.

A Ukrainian platoon commander told Ukrainian media that Russian forces were unleashing Storm-Z and Storm-V convicts as a first wave of attack, followed by elite Russian paratrooper units.

Ukraine recently passed a law to raise more than a quarter of a million new troops, but that will take months, and in the meantime, Ukrainian defenders are locally outnumbered. Ukrainian Colonel Pavlo Palisa, told Suspilne that Russian forces outnumbered the Ukrainians five to seven times over in Chasiv Yar.

On the western end of the front, the picture was more mixed.

Russian forces recaptured a section of Robotyne, a town in Zaporizhzhia which Ukrainian forces retook at great expense during their counteroffensive last year. But Syrskyii said Ukrainian forces managed to establish control over Nestryga Island in the Dnipro River Delta, which Russian forces had been using to harass Ukrainian positions on the right bank.

Ukraine’s allies stepped up their pledges of deliverable weapons from stockpiles as the situation on the ground deteriorated.

The UK announced its largest-ever military aid package to Ukraine on April 23, worth half a billion pounds ($625bn). The package comprises 400 armoured or all-terrain vehicles, 60 boats, and 1,600 missiles for air defence, attack and long-range strikes.

“We will never let the world forget the existential battle Ukraine is fighting, and with our enduring support, they will win,” Defence Secretary Grant Schapps said.

On Thursday, the Danish parliament voted overwhelmingly to increase aid to Ukraine this year by $590m, because the amount allocated for 2024 has already been mostly spent. That brought Denmark’s 2023-28 aid for Ukraine to $9.2bn.

Australia on Saturday announced a $100m military aid package to Ukraine, with half of it dedicated to short-range air defence.

On Monday, Germany announced a military aid package to Ukraine including a Skynex air defence complex, artillery rounds, and ammunition for IRIS-T air defence systems, Gepard anti-aircraft guns and other systems.

Allies have pledged a total of $95bn worth of weapons, NATO Secretary-General Jens Stoltenberg said, but much of that is in effect a wishlist, as the weapons have to be manufactured.

The latest pledge in this category came on Friday, when US Secretary of Defense Lloyd Austin announced a new six-billion-dollar package of military equipment through the Ukraine Security Assistance Initiative (USAI), which allows the US administration to order new equipment directly from manufacturers. However, the process will still take months.

Of more immediate effect was the billion dollars-worth of equipment the US shipped out last week, hours after US President Joe Biden signed into law a $95bn supplemental defence budget it took Congress almost six months to approve.

“US military assistance is currently en route to Ukraine and will take several weeks to arrive to frontline units and have tangible battlefield impacts,” wrote the Institute for the Study of War, a Washington-based think tank.

Virtually addressing a meeting of the Contact Group of Ukraine’s allies in Ramstein, Germany, Ukrainian president Volodymyr Zelenskyy said the new aid would enable Ukraine to go back on the offensive.

“Although … the Russian army managed to seize the initiative on the battlefield, we can still not only stabilise the front now, but also move forward, achieving our Ukrainian goals in the war,” said Zelenskyy.

Politico quoted three unnamed US officials saying they doubted whether that was possible.

Syrskyii struck a more sober note at Ramstein, saying the tactical and operational situation “has a tendency to worsen,” and stressed the urgent need for deliverable missiles, air defences and ammunition.

Stoltenberg on Monday admitted NATO allies had fallen short of their commitments during a surprise visit to Kyiv.

“Serious delays in support have meant serious consequences on the battlefield,” he said. “For months, the US was unable to agree a package. And European allies have been unable to deliver ammunition at the scale we promised. Ukraine has been outgunned for months … Russia has been able to push forward along the frontline. But it’s not too late for Ukraine to prevail.”