Russian forces are still edging forward in the shattered eastern Ukrainian city of Bakhmut, a Moscow-installed official said on Tuesday, but British intelligence said a Russian tank division had suffered heavy losses in the nearby town of Avdiivka.
The battle for Bakhmut, a mining city in the Donetsk region, has been the focus of Moscow's war in Ukraine for months, with both sides describing the fighting there as a "meat grinder".
Denis Pushilin, the Russian-installed leader of the part of Donetsk region under Moscow's control, said most Ukrainian forces had pulled back from the AZOM metals factory on the western side of the Bakhmutka river in the city.
"The important thing here was to clear out the industrial zone at the plant itself. You can practically say that has now been done, with the guys just finishing off (Ukrainian) fighters there who are only left in solitary groups," Pushilin told Russian state TV.
His claims ran counter to Ukrainian and Western assertions that the situation in Bakhmut is stabilising and that Russia's winter offensive is faltering.
Ukrainian military commanders have said their own counteroffensive - backed by newly-delivered Western hardware, including German Leopard 2 tanks - is not far off, but have stressed the importance of holding Bakhmut in the meantime.
Russian forces have also been shelling Avdiivka, 90km (55 miles) south of Bakhmut. Many civilians have now been evacuated.
In its daily update on the war in Ukraine on Tuesday, Britain's defence ministry said Russian forces had made only "marginal progress" in an attempt to encircle Avdiivka in recent days and had lost many armoured vehicles and tanks.
Russia's 10th Tank Regiment, taking part in the Avdiivka operation, was dogged by problems of ill discipline and poor morale, and had "likely lost a large proportion of its tanks", the ministry said.
In another sign of the pressure Moscow is facing, Russia said on Tuesday it had for the first time shot down a US-supplied GLSDB guided smart bomb fired by Ukrainian forces.
The Ground-launched Small Diameter Bomb, long sought by Kyiv to hit Russian command centres and supply lines, could double Ukraine's battlefield firing range.
Separately, Ukrainian forces reported repelling 62 Russian assaults along the eastern front over the past 24 hours.
Russian-installed officials in Donetsk city said Ukrainian forces killed two civilians late on Monday when they shelled an apartment building there. Reuters reporters saw rescuers combing through the rubble of the building, the lower part of which had collapsed, and one victim's legs protruding from the debris.
There was no immediate comment from Ukrainian authorities.
Reuters could not verify the battlefield reports.
In Semenivka village a few kilometres (miles) north of Avdiivka, 71-year-old Lyubov hunkered down in her home listening to regular artillery explosions while looking after her cow.
"Strikes take place in the morning, in the evening, at lunch. They’re unpredictable," she said, adding that she refused to leave as she was too old and didn't have enough money. “Everyone is buried here, including my parents."
Tactical nuclear weapons
Russian President Vladimir Putin's invasion, now into its 14th month, has been bogged down for months in eastern Ukraine.
In warnings to the West against continuing to arm Ukraine, Putin and other Russian officials have increasingly played up the risks of nuclear weapons being used in the war. On Saturday, Putin said he had struck a deal to station tactical nuclear weapons in neighbouring Belarus, an ally of Moscow.
Belarus's foreign ministry said on Tuesday it had agreed to host the nuclear weapons to protect itself after years of "unprecedented pressure" from the West. It said the move did not contravene international non-proliferation agreements.
Ukraine and its Western allies have denounced the plan.
Polish Prime Minister Mateusz Morawiecki said Belarus would face further European sanctions as a result.
The war has devastated Ukrainian cities and towns, caused the deaths of tens of thousands of people and forced millions more to flee their homes, while also sharply raising global food and energy prices and exacerbating tensions worldwide.
Russia's defence ministry said on Tuesday its navy had fired supersonic anti-ship missiles at a mock target in an exercise in the Sea of Japan, prompting Tokyo - a key Western ally - to warn of increased Russian military activity in the Far East region.
France will double its supplies of 155mm shells to Ukraine to about 2,000 a month, its defence minister said on Tuesday. Ukraine has said these shells are critical to its war effort.
President Volodymyr Zelensky, in his nightly video address on Monday, accused Russian troops of holding the Zaporizhzhia nuclear plant "hostage", calling this "radiation blackmail", and said its safety could not be guaranteed until they left it.
Russian troops have occupied the nuclear power plant, Europe's largest, since the early weeks of the invasion of Ukraine and have shown no inclination to relinquish control.
Rafael Grossi, director-general of the International Atomic Energy Agency (IAEA), told Reuters in an interview in Dnipro that his efforts to broker a deal to protect the plant were still alive, and that he was adjusting the proposals to seek a breakthrough.
"I am confident that it might be possible to establish some form of protection, perhaps not emphasising so much the idea of a zone, but on the protection itself: what people should do, or shouldn't do to protect (the plant) instead of having a territorial concept," he said.
Russia and Ukraine routinely accuse each other of shelling the Zaporizhzhia plant. Grossi has repeatedly called for a safety zone around it and is due to visit it again this week.