The fall of the city means that Ukraine will face an even tougher fight

With the Russian army's capture of the eastern Ukrainian city of Avdiivka on Saturday, the front line has shifted significantly, paving the way for the next grueling chapter of the war as Ukrainian forces withdraw and Russian forces re-form for future attacks .

Ukraine's defeat in the embattled city, which has been under attack since 2014 as Russian-backed separatists battled government forces for control of the country's east, comes at a particularly dangerous time. As Russia's large-scale invasion enters its third year, Ukrainian forces are running low on ammunition and facing a growing troop shortage.

During the withdrawal from Avdiivka, these problems are exacerbated by the flat and unforgiving terrain outside the city. Without dominant hills, larger rivers, or extensive fortifications of the kind it has built around Avdiivka for the better part of a decade, Ukraine will likely have to cede more ground to hold back Russian units.

“They don't have an established secondary line to fall back on,” Michael Kofman, a Russia expert at the Carnegie Endowment for International Peace in Washington, said in a telephone interview. “A lot depends on whether the Russian forces can continue to push forward or whether they run out of momentum.”

Even now, despite heavy losses during their attack on Avdiivka, Russian forces are putting pressure on various parts of the 900-kilometre-long front line, hoping that Ukraine cannot defend itself everywhere at once.

Where Russia will try to move forward next is not yet known. The northeastern city of Kupiansk, the eastern city of Khasiv Yar and the southern village of Robotyne are all under threat, even as smoke still hangs around the ruins of Avdiivka.

In recent months, deep anti-tank trenches have appeared around eastern Ukrainian towns and villages near Avdiivka, such as Pokrovsk, about 30 miles (48 kilometers) to the west. But closer to the fighting, especially near Avdiivka, it is unclear whether the Ukrainian brigades have the resources to withstand a new offensive, such as the one that surrounded the battle. city, or whether Russian forces can continue attacking after months of sustained fighting.

Ukrainian Defense Minister Rustem Umerov said plainly in a Facebook post on Saturday that some of the lessons learned from the city's fall include the need to “build and strengthen” fortifications.

The Russian army's tactic of using its enormous size to overwhelm the smaller Ukrainian army enabled its most decisive battlefield victories after the defeats around Kiev, Kharkov and Kherson in 2022.

But nearly two years later, military aid to Ukraine from Western allies, especially the United States, has dwindled to a trickle due to political infighting in Washington, leaving Russia plenty of room to gain fire superiority. Ukraine has tried to bridge that gap with self-exploding drones, but is far from achieving any kind of parity with Russia's armed forces, Ukrainian troops say.

U.S. officials said it is not too late to strengthen Ukrainian forces if more aid can be provided quickly. An infusion of artillery and other munitions could prevent the tense Russian forces from launching another attack any time soon.

But in the absence of additional support, the officials added, Russia will ultimately build on its victory in Avdiivka and continue to push back Ukrainian units and capture more of eastern Ukraine, one of the main war objectives the Kremlin.

Avdiivka, with a pre-war population of about 30,000 people, was practically a fortress when Russian forces launched their major assault last fall. The Kremlin's military formations suffered thousands of casualties and a significant loss of tanks and other armored vehicles, while Ukrainian forces held their ground.

Still, the Russian forces continued to apply pressure, with the infantry attacking in smaller groups. That change in tactics, coupled with an increasing number of drones, a much larger amount of artillery and a flood of airstrikes, pushed Ukraine's beleaguered forces to the breaking point.

“One of the key events of 2023 was that Russia was able to recruit a large number of volunteers,” said Rob Lee, a senior fellow at the Foreign Policy Research Institute based in Philadelphia. “The downside is that this is happening at a time when Ukraine is facing mobilization problems.”

Ukrainian leaders responded to the mounting pressure by sending in a mix of special forces and the Third Separate Assault Brigade, a veteran infantry unit with a far-right background, to fill the gap and ultimately aid the retreat. A soldier from the brigade said they had been taken off the front line around the eastern city of Bakhmut in recent months and had only a short time to recover before being sent to Avdiivka as firefighters.

The depletion of one of Ukraine's best units during a time of crisis, military analysts say, points to a growing problem in Ukraine's ranks: There are simply not enough troops to go around on the front.

“Ukraine sent its best units because the forces in Avdiivka were steadily depleted and had to withdraw,” Mr Kofman said. “In addition to a lack of ammunition, Ukraine has serious manpower problems, especially when it comes to infantry.”

Although Ukrainian officials keep the number of casualties secret, a recent effort by military officials to mobilize another 500,000 troops underlines the toll of a war that appears far from over. Morale is also declining, Ukrainian soldiers said in recent weeks, worsened by troop and ammunition shortages, rising casualties and shorter lengths of stay at the front.

But the question remains how and where exactly this will turn out on the battlefield.

Julian E Barnes contributed reporting from Washington.