MOSCOW - Russia said on Wednesday that its forces were advancing north inside the Ukrainian city of Pokrovsk and clearing out Kyiv's troops in a drive to take full control of what has been an important transport and logistics hub for the Ukrainian army.

Ukraine has acknowledged its troops face a difficult position in the strategic eastern city, which Russia has been trying to capture for more than a year, but denies they are surrounded and says reinforcements are on their way.

Russia sees the city as the gateway to its capture of the remaining 10%, or 5,000 square km (1,930 square miles) of Ukraine's eastern industrial Donbas region, one of its key aims in the almost four-year-old war.

"Assault groups of the 2nd and 51st armies continued to destroy surrounded Ukrainian Armed Forces units in the residential area of the Prigorodny microdistrict, in the eastern part of the Central District and in the private sector (where there are residential houses)," the Russian Defence Ministry said in a statement.

"The offensive in the northern direction continues," it added, saying its forces were also clearing Ukrainian troops from settlements on Pokrovsk's southeastern flank and had repelled numerous Ukrainian attempts to break out of encirclement.

The Ukrainian military said on Tuesday that fierce fighting was under way in a part of Pokrovsk that was key for Kyiv's frontline logistics and that additional special forces had arrived there, with more weapons and equipment being sent.

There was no immediate comment from Ukraine on the situation in Pokrovsk on Wednesday.

Ukrainian President Volodymyr Zelenskiy said on Monday the area around Pokrovsk remained under severe pressure but up to 300 Russian servicemen still in the city had made no gains in the past day and there were just 60 in another city, Kupiansk.

The Russian Defence Ministry said either he had no grasp of what was happening on the ground or he was deliberately trying to conceal the parlous situation for Kyiv's forces.

Ukrainian units were tr...