Russia’s advance seems to have stalled in Moscow’s campaign to capture the eastern Ukrainian city of Bakhmut, a leading think tank has said in an assessment of the longest ground battle of the war.

The Washington-based Institute for the Study of War (ISW) said there have been no confirmed advances by Russian forces in Bakhmut.

Russian forces and units from the Kremlin-controlled paramilitary Wagner Group continue to launch ground attacks in the city, but there has been no evidence they have been able to make any progress, ISW said late on Saturday.

The report cited the spokesman for the Ukrainian Armed Forces’ Eastern Group, Serhii Cherevaty, saying that fighting in the Bakhmut area has been more intense this week, including 23 clashes in the city over the previous 24 hours.

The ISW’s report follows claims of Russian progress earlier this week.

The UK’s Ministry of Defence (MoD) said on Saturday that paramilitary units from the Kremlin-controlled Wagner Group have seized most of eastern Bakhmut, with a river flowing through the city now marking the front line of the fighting.

The assessment highlighted that Russia’s assault will be difficult to sustain without more significant personnel losses.

The mining city of Bakhmut is located in Ukraine’s eastern Donetsk province, one of four regions of Ukraine that Russian President Vladimir Putin illegally annexed last year.

Russia’s military opened the campaign to take control of Bakhmut in August, and both sides have experienced staggering casualties.

Ukrainian President Volodymyr Zelensky has vowed not to retreat.

In its latest report on Sunday, the UK’s MoD said the impact of the heavy casualties Russia is continuing to suffer in Ukraine varies dramatically across the country.

Its intelligence update said the major cities of Moscow and St Petersburg remain “relatively unscathed”, particularly among members of Russia’s elite.

In contrast, in many of Russia’s eastern regions, the death rate as a percentage of the population is “30-40 times higher than in Moscow”.

The report highlighted that ethnic minorities often take the biggest hit.

In the southern Astrakhan region, for example, about “75% of casualties come from the minority Kazakh and Tartar populations”.

Russia’s mounting casualties are reflected in a loss of government control over the country’s information sphere, ISW said.

The think tank said Russian Foreign Ministry spokeswoman Maria Zakharova confirmed “infighting in the Kremlin inner circle” and that the Kremlin has effectively ceded control over the country’s information space, with Mr Putin unable to readily regain control.

The ISW sees Ms Zakharova’s comments, made at a forum on the “practical and technological aspects of information and cognitive warfare in modern realities” in Moscow, as “noteworthy” and in line with the think tank’s longstanding assessments about the “deteriorating Kremlin regime and information space control dynamics”.

Elsewhere in Ukraine, Russian attacks over the previous day killed at least five people and wounded another seven across Ukraine’s Donetsk and Kherson regions, local Ukrainian authorities reported on Sunday morning.

Donetsk Governor Pavlo Kyrylenko said two people were killed in the region – one in the city of Kostyantynivka and one in the village of Tonenke. Another four civilians were wounded.

Local officials in southern Kherson province confirmed that Russian forces fired 29 times on Ukrainian-controlled territory in the region on Saturday, with residential areas of the regional capital, Kherson, coming under fire three times. Three people were killed and a further three injured.

In Ukraine’s north-eastern Kharkiv province, the Kharkiv, Chuhuiv and Kupiansk districts came under fire, but no civilian casualties were reported.

The head of Ukraine’s southern Mykolaiv province, Governor Vitali Kim, said on Sunday morning that the town of Ochakiv, at the mouth of the Dnieper River, came under artillery fire in the early hours of Sunday.

Cars were set on fire, while private houses and high-rise buildings were damaged, but no casualties were reported.