Russian forces were ramping up attacks in eastern Ukraine on Wednesday, Moscow and Kyiv said, as they vie to secure elusive territorial gains before the end of the year.
Despite the frontlines having barely shifted in 2023, fighting has remained intense, with the nearly encircled industrial town of Avdiivka the latest major flashpoint.
Russia launched a renewed bid to capture the war-battered town last month and analysts suggest Moscow's forces have made incremental gains, though at an enormous human cost.
"The enemy has doubled its artillery fire and airstrikes. It has also intensified ground infantry attacks, and is using armoured vehicles," said Oleksandr Shtupun, a spokesman for Ukraine's army.
Improving weather conditions -- following powerful storms across southern Ukraine and Russia earlier this week -- have enabled Russia's forces to intensify their assaults and use drones again, he said.
Oleksandr Tarnavsky, the Ukrainian commander responsible for the area, also said Russia had "significantly increased" its activity around Avdiivka.
He said Russian forces had carried out nearly 20 airstrikes, launched four missiles, thrown 56 assault waves at his forces, and fired more than 1,000 artillery rounds.
Meanwhile, the chief of the International Atomic Energy Agency expressed renewed concern Wednesday over increased fighting near the southeastern Zaporizhzhia nuclear power station that has remained under Russian control since the invasion.
"Military actions have increased, and... we are seeing a multiplication of attacks in the vicinity," Rafael Grossi told reporters in France. "This is of great concern to us."
'Holding the line'
Avdiivka sits in a strategically important indent in the Russian frontlines of the Donetsk region, with Russia's troops surrounding the town on almost three sides.
Defensive fortifications on its southern edge are just five kilometres (3 miles) north of Donetsk city, the capital of a region Moscow claimed to have annexed last year.
Ukraine has so far held off the Russian bombardment and still controls an eight-kilometre-wide strip of land -- and a vital supply road -- stretching from Avdiivka to the northwest.
Amid the resistance, Russian losses around the city are mounting.
British intelligence said that recent weeks had "likely seen some of the highest Russian casualty rates of the war so far."
But an advisor to Ukrainian President Volodymyr Zelensky cautioned on Wednesday that Moscow was prepared to throw "unlimited" numbers of soldiers into the war.
"Russia still has unlimited human resources that it ruthlessly uses for conducting so-called 'human wave attacks'. They'd rather use people than machinery," Mykhailo Podolyak wrote in a social media post.
Around 50 kilometres (30 miles) north, Russia's military claimed separately it had taken control of Khromove, a small village on the outskirts of Bakhmut.
"Troops, supported by aviation and artillery fire, improved their positions along the front line and liberated the village of Artemovskoye," Russia's defence ministry said in a daily briefing, referring to the village by a previous version of its name.
AFP was unable to verify either side's claims.
Both Moscow and Kyiv also said they had downed enemy drones and missiles overnight.
Ukraine is bracing for Russia to increase its attacks on its energy infrastructure in a repeat of Moscow's tactics last winter, which saw millions left without power and heating for hours in sub-zero temperatures.
The national energy company Ukrenergo reported a shortage of electricity on Wednesday following storms earlier this week.
Ukraine's air force said it downed all 21 drones and two of three X-59 guided missiles that Russia had fired at its territory overnight.
The third missile did not reach its target, it added.
Poison plot
Russia said it downed a Ukrainian drone flying towards the capital Moscow and another over the southern Rostov region, the military headquarters for its invasion.
Meanwhile, Ukrainian officials reported a 68-year-old man was killed in a Russian shelling attack on the suburbs of the southern Kherson city.
The Kremlin on Wednesday also responded to Ukrainian claims that Moscow had poisoned the wife of its military intelligence chief.
Marianna Budanova, the wife of Ukraine's spymaster Kyrylo Budanov, was hospitalised with heavy metals poisoning, in what intelligence figures in Kyiv allege was a brazen assassination attempt.
"Ukraine blames Russia for everything. Even its own existence, it seems to me," Kremlin spokesman Dmitry Peskov told reporters in response to the allegations.
On the diplomatic front, US Secretary of State Antony Blinken on Wednesday told a NATO meeting that Washington and its allies remained steadfast in their backing for Ukraine, as doubts escalate over the West's commitment as the war appears to have ground to a stalemate.
Poland also reiterated support for Kyiv by announcing it was boycotting an international security meeting due Thursday over the invitation of Russian Foreign Minister Sergei Lavrov.
Poland's Foreign Minister Szymon Szynkowski vel Sek said he would not participate in the meeting of the Organization for Security and Co-operation in Europe (OSCE) nor will he send any of his deputies, while calling Lavrov's presence "unacceptable".
Tensions with Moscow were also brewing in Estonia with Tallinn saying it was preparing to close its border with Russia, citing potential "hybrid attacks" by its eastern neighbour.