Ukrainian troops are holding out in Soledar despite Russian claims to have captured the town in the east of the country, British defence chiefs said on Monday.
The Ukrainian forces were also gradually seizing more ground near Kremina, which has also been at the centre of fierce fighting.
In its latest intelligence update, the Ministry of Defence in London said: “Over the weekend, intense fighting continued in both the Kremina and Bakhmut sectors of the Donbas front.
“As of 15 January 2023, Ukrainian Armed Forces (UAF) almost certainly maintained positions in Soledar, north of Bakhmut, in the face of continued Wagner Group assaults.”
The Wagner Group, Vladimir Putin’s “private army”, is reported to be vying for power against the Russian regular army during the clashes over Soledar.
Both claimed last week that Soledar in the eastern Donbas region had fallen under Russian control, but Ukrainian military chiefs said their forces were still defending the town.
The UK MoD briefing added: “Around Kremina, fighting has been characterised by a complex series of local attacks and counter-attacks in wooded country. However, overall, the UAF continue to gradually advance their front line east on the edge of Kremina town.
“Over the last six weeks, both Russia and Ukraine have achieved hard-fought but limited gains in different sectors.
In these circumstances, a key operational challenge for both sides is to generate formations of uncommitted, capable troops which can exploit the tactical successes to create operational breakthroughs.”
Russian forces claimed to have taken control of Soledar, which has 200km (124 miles) long salt mines which could be used to hide weapons.
But Ukraine insisted on Sunday that its forces were battling to hold the town, with street fighting raging and Russian forces advancing from various directions.
“Put simply, THE BATTLE CONTINUES,” Deputy Defence Minister Hanna Maliar said on the Telegram messaging app. “Everything else is unverified information.”
The General Staff of Ukraine’s Armed Forces morning report on Monday detailed another wave of more than 55 Russian missile and rocket attacks in the past 24 hours.
It said 25 settlements in the Bakhmut area, including the towns of Soledar and Bakhmut itself, were hit, along with various targets, including civilian infrastructure, in the Zaporizhzhia, Dnipropetrovsk and Kherson regions.
Britain, the US, Ukraine and its allies are fighting an information war against Moscow so their briefings need to be treated with caution, but are far more believable than the propaganda and denials issued by the Kremlin, including that its military is not targeting civilians.
Ukrainian officials on Monday saw little hope of pulling any more survivors from the rubble of an apartment block in the city of Dnipro which was hit by a major Russian missile attack, with dozens of people expected to have died.
Valentyn Reznichenko, governor of the Dnipropetrovsk region, said on Monday that 35 people were confirmed dead so far and the fate of 35 more residents remained unknown.
"The search for people underneath the rubble continues," Mr Reznichenko said on the Telegram messaging app.
Ukraine's Air Force said the apartment block was struck by a Russian Kh-22 missile, which is known to be inaccurate and that Ukraine lacks the air defences to shoot down. The Soviet-era missile was developed during the Cold War to destroy warships.
Moscow has been pounding Ukraine's energy infrastructure with missiles and drones since October, causing sweeping blackouts and disruptions to central heating and running water.
In his nightly address after the Dnipro strike, Ukraine’s president Volodymyr Zelensky called on Western allies to supply more weapons to end "Russian terror" and attacks on civilian targets.
On Saturday, Britain followed France and Poland with promises of further weapons, saying it would send 14 of its Challenger 2 main battle tanks as well as other advanced artillery support in the coming weeks.
The first despatch of Western-made tanks to Ukraine is likely to be viewed by Moscow as escalation of the conflict.
