Ukraine's fortress belt, a strategic line of five towns and cities in the Donbas, is crucial to Kyiv's defence and the site of the war's most brutal fighting. The urban settlements, combined with rising ground, woodland, and the Kryvyi Torets and Kazenyi Torets rivers, form the biggest obstacle to Russian advances. Ukraine fears that if the belt falls, it could open a path across sparsely built-up lowlands to key cities including Dnipro, Kharkiv, and Kyiv.
Lyman: The Northern Outpost
The small city of Lyman, the northern outpost of the fortress belt, is covered in a vast cobweb of spent fibre-optic cable used to control drones. The accumulation is so dense that fresh drones struggle to fly through it. Residential blocks are shattered from shellfire as Moscow's forces push daily to retake the city, which they briefly occupied until the Ukrainian counteroffensive of 2022. About 1,000 civilians remain, living in cellars without electricity, gas, or running water. Oleksandr Pavlovych, a vegetable seller, fled after his 78-year-old mother died from shrapnel wounds. He buried her in the garden and cycled 19 miles to safety, surviving a drone attack that exploded on an anti-drone net. "The city is so badly damaged," he said. "Outside the drones are everywhere."
The Strategic Importance of the Belt
The fortress belt was identified for its potential strengths in 2015 under President Petro Poroshenko, after Russia seized Crimea. The strategy foresaw a defensive line based around four large cities in Donetsk oblast and their satellite settlements, running 30 miles north to south along the H-20 Kostyantynivka-Sloviansk main road. The area features dense urban centres, sprawling industrial facilities, and complex geography of rivers, woods, and rising terrain. The Institute for the Study of War described it as "optimised for defence across nearly every possible topographical and geographical characteristic" and noted that the high costs Russia paid in Bakhmut or Pokrovsk would pale in comparison to those needed to seize the fortress belt.
Transformed Warfare and Defences
Warfare has been transformed over the course of the conflict. Brigades now traverse the front in vehicles bristling with spikes to pre-detonate drones or caged in wire grilles. Defences include tank ditches, bollards, barbed wire, antenna to spot drones, electronic countermeasures, and anti-drone net tunnels over streets and highways. Lt Col Shamil Krutkov of Ukraine's 93rd brigade said, "Technology has turned everything upside down. We have had very tough fights, but those hard times forced us to think and be creative." He added that both sides have similar technologies, making large offensives difficult. "The situation over the years has gone from where we might be facing a Russian regiment to two Russians trying to infiltrate."
Coordinated Defence and Kill Zones
Vadym, an officer in the 63rd brigade fighting near Lyman, credited military reforms in 2024 for improving coordination. "Before, a single brigade would hold its position and then be outflanked. Now we started creating proper kill zones, clearing forests, digging tank ditches, and laying obstacles. Over the last six months in our sector we haven't given the Russians a single metre." Russian forces have advanced in places, such as Kostyantynivka, where they occupy the east side, but at huge cost in lives.
Civilian Life Under Constant Threat
In Sloviansk and Kramatorsk, factories and apartment buildings show evidence of daily strikes. Petrol stations are netted, fuel pumps sandbagged, and concrete shelters provided. When FPV drones appear multiple times daily, a continuous siren sounds. Yulia Melnyk, 46, whose apartment in Kramatorsk was damaged by a Shahed drone, said, "Sometimes the noise scares me. But if I'm hearing the explosion, I'm alive and life goes on." Recently installed drone nets allow residents to shop but offer no protection against larger drones and glide bombs.
The Human Cost
At an evacuation centre in Sloviansk, Lyudmilla, 68, escaped from a village two miles from Russian lines after a glide bomb killed her husband and two other men. "For the last two years we have been living in the cellar. I don't feel safe in Sloviansk," she said. Vadym noted that defending one town helps defend others, but interconnectedness could be a vulnerability if logistics routes are cut. "Obviously if we lose Lyman, then it's a problem for Sloviansk. But that's if ..." He observed a change in perception: "Back then they said: 'Why hold on to this?' Now it's the opposite. We need to build up our strength to gain a tactical advantage."
