Ukraine’s months-long preparation for its next counteroffensive to try to wrest back occupied territory has allowed Russia to fortify its positions along the almost 1,000km frontline.
Satellite images reviewed by the Financial Times and analysed by military experts revealed a multi-layered Russian network of anti-tank ditches, mazes of trenches, concrete “dragon’s teeth” barricades, steel “hedgehog” obstacles, spools of razor wire and minefields.
“Russian forces really seemed to realise . . . that a lot of the terrain they had control over was going to be difficult to defend without entrenched positions,” said Brady Africk, an open-source intelligence researcher and analyst at the American Enterprise Institute who is tracking and mapping Russia’s defensive build-up.
Russia began digging in “in earnest” in November and when its troops took new territory they worked quickly to entrench themselves, he said, adding that Russian forces had “ramped up” work on their fortifications recently.
“There was a brief lull in winter, likely due to [the] ground freezing and it becoming more difficult to dig,” Africk said. “But since the ground has softened, we’ve seen the digging of fortifications escalate dramatically, particularly in the past few months.”
Military analysts said these fortifications would not be enough to stop Ukrainian troops from advancing, but were likely to slow the offensive.
The stakes for Ukraine are high. A successful operation could give it significant momentum as it tries to drive out Russian troops, convince western partners to continue their military support, and give Kyiv leverage in any future negotiations with Moscow. It would also help keep morale high among Ukraine’s defiant but fatigued population, which has endured the horror of Russia’s full-scale invasion for 15 months.
There is also much at stake for Russia. If Ukraine can take back control of the provinces of Donetsk, Luhansk, Kherson and Zaporizhzhia — which Russian president Vladimir Putin claimed to have annexed last September — or of the Crimean Peninsula, which the Kremlin seized in March 2014, it could deal a significant blow to a military already showing signs of exhaustion and infighting.
Early signs of Ukraine’s counteroffensive can already be seen in what military experts refer to as “shaping operations” — common tactics used ahead of a large-scale attack. Over the past two weeks, Ukraine’s forces have carried out missile strikes and sabotage on Russian command and control centres, weapons depots and artillery systems.
Drone attacks and explosions targeting military facilities in Russia, and even the Kremlin itself, also suggest Ukrainian involvement, according to analysts, despite Kyiv’s denials. Before Moscow claimed to have captured the embattled eastern city of Bakhmut this weekend, Ukrainian troops had attacked Russian forces on their northern and southern flanks, recapturing a few square kilometres of territory — their first gains in the area in months.
But observers are yet to see a massive thrust along the lines of the Ukrainian counteroffensive last autumn, when Kyiv’s forces swept through the north-eastern Kharkiv region and recaptured the southern city of Kherson.
Breaking through Russia’s multi-layered defensive lines without sustaining heavy losses would be extremely difficult, said Mykola Bielieskov, a research fellow at the Kyiv-based National Institute for Strategic Studies.
Success would require synchronising different units deploying armoured vehicles, artillery, mine-clearing and air defence, he added.
“On their own, obstacles don’t stop advancing forces,” Bielieskov said. “They will only [be effective] if manned properly and complemented with artillery fire, aviation and manoeuvre of reserves.”
Rob Lee, a senior fellow at the Foreign Policy Research Institute, an American think-tank, said Russia’s fortifications were designed to funnel Ukrainian troops towards areas where they would come under intense fire.
“If you have multiple lines of defence, even if Ukraine punches through the first one successfully, then Russia should have enough time to reinforce a second or third,” he said.
The south is likely to be the main focus for Ukrainian forces — something not lost on Moscow even as Ukrainian president Volodymyr Zelenskyy and his military leaders have kept operational plans a closely guarded secret, experts say.
“Around November and certainly continuing into the new year, [Russian forces] ramped up construction, particularly in southern Ukraine,” Africk said. “The topography there is a lot flatter and there are wide open fields. It became a priority for Russian forces to make sure they had defensive lines [there].”
Satellite images show Russia’s most heavily fortified section of the frontline is in the southern Zaporizhzhia province, where Ukraine is expected to try to break through and sever the “land bridge” connecting Russian territory with occupied Crimea. The connection is crucial for Russian military logistics and supplies.
Russia has constructed an elaborate maze of anti-tank ditches, trenches, concrete and steel obstacles, razor wire and minefields in the area. The Berdyansk airfield near the Sea of Azov, a hub for Russian military aircraft, has been surrounded by deep trenches and three lines of concrete “dragon’s teeth”.
Melitopol and Berdyansk were “obvious” locations for Russian fortifications, Lee said. If Ukraine took either, it would gain significant ground and enable its forces to carry out onward campaigns more effectively, he added.
The northern border of Crimea has also been heavily fortified. The defences stretch from Armyansk in the north to Dzhankoi in the north-west. Both are crucial transport hubs and gateways to the peninsula. Dzhankoi also hosts a Russian military airfield.
Ukraine is likely to utilise the size of the battlefield to try to catch its enemy off guard. Despite Russia’s extensive defences, the sheer length of the frontline meant the Kremlin’s forces would be stretched, experts said.
“The length of the frontline works to our advantage,” said Andriy Zagorodnyuk, chair of the Ukrainian Centre for Defence Strategies and a former defence minister of Ukraine. “[Russian troops] are scattered around this frontline and we will always be able to find areas where they don’t expect us.”
Dara Massicot, a senior policy researcher at the Rand Corporation, a US global policy think-tank, said Russia’s performance would depend on several factors, including whether their frontline was manned by “exhausted or maltreated, inadequately trained personnel”.
“The morale of Russian soldiers is variable, from tired to bad — it matters,” she said.
Lee said other factors included whether Russia had exhausted its munitions trying to capture Bakhmut — the longest and bloodiest battle of the past year — and whether its newly mobilised forces were ready for the coming fight.
“They don’t necessarily have that much combat experience. A lot of them have been just holding trenches,” he said. “Will they stay in the fight, or will they run?”
Cartography by Steven Bernard