Kyiv - On Wednesday, Yevgeny Prigozhin, the head of Russia's Wagner mercenary group, claimed that his forces had taken full control of the eastern part of the Ukrainian city of Bakhmut even as Ukrainian defenders remained defiant as one of the bloodiest battles of the year-long war ground on amid the ruins.

The victory would mean that Russian forces now control nearly half of the city in their costly push to secure their first significant victory in several months.

Ukrainian military and political leaders now speak of hanging on to positions and inflicting as many casualties as possible on the Russians. The General Staff of Ukraine's armed forces said in its Wednesday morning report that the enemy, despite significant losses, continues to storm the town of Bakhmut.

In Stockholm, NATO Secretary-General Jens Stoltenberg struck a pessimistic note. Speaking before a meeting of European Union defence ministers, he said Russia was throwing more troops into the battle. He added that they had suffered significant losses, but at the same time, "we cannot rule out that Bakhmut may eventually fall in the coming days." This would not necessarily be a turning point in the war, he added, but it showed that "we should not underestimate Russia, we must continue to provide support to Ukraine."

Russia claims to have annexed nearly 20% of Ukraine's territory and says that taking Bakhmut would be a step towards seizing the whole of the eastern industrial Donbas region, made up of Donetsk and Luhansk provinces. Western analysts say Bakhmut has little strategic value, although its capture would be a boost to President Vladimir Putin and his military after a series of setbacks in what they call their "special military operation" in Ukraine.

Kyiv says the losses suffered by Russia there could determine the course of the war, with decisive battles expected when the weather improves and Ukraine receives more Western military aid, including heavy battle tanks.

The months of warfare in the east have been among the deadliest and most destructive since Russia invaded in February last year, adding Bakhmut's name to a list of devastated cities such as Mariupol, Sievierodonetsk, and Lysychansk.

A Ukrainian military drone showed the scale of destruction in Bakhmut, filming apartment blocks on fire and smoke billowing from residential areas. Iryna Vereshchuk, a deputy Ukrainian premier, said fewer than 4,000 civilians - including 38 children - out of a pre-war population of some 70,000 remained in the city, now largely in ruins after months of bombardment.

In Stockholm, EU defence ministers met to discuss further arms supplies to Kyiv. Shipments of battle tanks and artillery are already in the pipeline, but it could take months before they can be put into action on the front lines.