Russia’s retreat from northeastern Ukraine is a setback for Moscow, but it opens the door to the possibility of an even greater one: that Ukrainian forces, galvanized by their success, will sweep south to try to reclaim territory in the eastern Donbas region that has been one of the Kremlin’s main objectives in the war.
Russian forces occupy most of Donbas, but already there are signs that the government in Kyiv is challenging its grip. On Wednesday, Ukrainian forces were fighting on the outskirts of the city of Lyman, according to Ukrainian officials.
Donbas is made up of two regions, Donetsk and Luhansk, where Russia has supported separatist uprisings since 2014. On Wednesday, the head of the separatist Donetsk People’s Republic, Denis Pushilin, said that Ukraine wanted to reclaim Lyman and use it as a springboard to attack Luhansk, reported Tass, a Russian state news agency. Mr. Pushilin said the effort would fail.
The situation on the front line remains murky. On Tuesday, the exiled governor of Luhansk, Serhiy Haidai, said in a Twitter post that Russian forces had abandoned the town of Kreminna, which is in Luhansk and lies east of Lyman, though on Wednesday he said they had returned and torn down Ukrainian flags. “They are giving the appearance of having a large presence in the city,” he tweeted.
Ukrainian control of those locations would be strategically significant. It would indicate that fighting has extended beyond a new defensive line that Russia’s Defense Ministry established following its pullback in the northeast. And it would suggest that the city of Sievierodonetsk, which Russian forces captured at the end of June after a prolonged fight that brought huge casualties on both sides, could be vulnerable to a counterattack.
Lyman stands on an access road that runs west from Sievierodonetsk, while Kreminna lies to its north. Any advance would make Sievierodonetsk, and the twin city of Lysychansk, more vulnerable to Ukrainian artillery, military analysts said.
“Everything north of Sievierodonetsk and that area is in a bit of turmoil” for Russia, said Jack Watling, a senior fellow at the Royal United Services Institute, a research institution in London. He said that the defeat in the northeast had effectively caused the collapse of one of Russia’s four military groupings in Ukraine, but added: “I don’t see the morale shock effect cascading into other groups of forces.”
In recent weeks, Moscow has shifted some of its forces in Donbas to southern Ukraine to defend against a Ukrainian counteroffensive there. Even so, military experts said, some of its most effective forces remain in Donbas, bolstered by separatist fighters.