President Volodymyr Zelensky has said "this is what madness looks like" to describe the fighting around Soledar in Ukraine's east.
Russian troops and the Wagner Group of mercenaries have been trying to capture the town as part of overall plans to take control of Bakhmut – just 10km further south in Ukraine's Donetsk region.
The Ministry of Defence said earlier this week that most of the settlement of Soledar – near the last known location of two missing British citizens – is now likely controlled by pro-Moscow forces.
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Fighting in the region has been intense and Ukrainian officials have said the clashes have brought new levels of death and devastation in the months-long conflict.
President Zelensky added: "The whole land near Soledar is covered with the corpses of the occupiers and scars from the strikes."
The Soledar axis is "highly likely" an effort to envelop Bakhmut from the north and disrupt Russia's lines of communication, according to UK defence intelligence.
Defence and security expert Glen Grant told Forces News: "If Bakhmut and Soledar get cut off, then Russia will have a breakthrough gap that they can then head west into the Donetsk region and take more ground, which is what they're trying to do."
The Russians and Wagner group are thought to be attracted to Soledar because of its 200km-long disused salt mines.
Some of the fighting has focused on their entrances, which run underneath the district.
The MOD says that both sides are likely worried the tunnels could be used for infiltration behind their lines.
There is also a financial incentive to taking control of the mines.
Mr Grant explained: "The salt mines were giving something like close to 20% of the Russian salt so that is, actually, in economic terms, quite a lot.
"So those salt mines, once captured, represent money and this is one of the big things that people are saying that the Wagner Group have been concentrating on Bakhmut purely to capture the salt mines and there are other mines down there as well, there are other minerals."
Despite the increased pressure on Bakhmut, Russia is unlikely to take the town anytime soon, due to stable Ukrainian defensive lines and control over supply routes, the MOD added.
Both sides have taken heavy losses and President Zelensky has praised his troops for their resilience.
Mr Grant added: "Their [Russia's] military advantage at the moment is just throwing as many ex-prisoners as they can at the Ukrainians and this is a completely different battle style to the mobilised troops because with the mobilised troops, if the Ukrainians hit them hard, then they run away.
"The Wagner prisoners don't tend to run away, and they tend to be much more risk takers and much more willing to die, in effect."
The heavy losses and style of fighting have led analysts to draw comparisons with the trench warfare of the First World War.