Ukrainian President Volodymyr Zelensky has visited the frontline near Bakhmut where fierce fighting rages on.
The beleaguered city has become a focal point of the war, with Russia trying to capture it for months.
The UK's Ministry of Defence (MoD) said Ukrainian forces recently launched a counter-attack to the west of the city.
Mr Zelensky's visit comes after Russian forces attacked Ukrainian cities overnight, killing at least four people in a drone strike near the capital.
The Ukrainian leader thanked troops around Bakhmut for their defence of the city and country, a statement said.
"I am honoured to be here today," the Ukrainian president told his servicemen, "in the east of our country, in Donbas, and to award our heroes, to thank you, to shake your hands."
Bakhmut lies in ruins. For more than seven months, it has witnessed fierce fighting as Russian forces try to make territorial gains to please the Kremlin.
The MoD said Ukraine's counter-attack to the west of Bakhmut was likely to relieve pressure on the main supply route to the city - and said Russia's attack on the city could be losing momentum.
"Fighting continues around the town centre and the Ukrainian defence remains at risk from envelopment from the north and south," the statement added.
"However, there is a realistic possibility that the Russian assault on the town is losing the limited momentum it had obtained, partially because some Russian [military] units have been reallocated to other sectors."
Earlier, Mr Zelensky said Moscow had launched more than 20 "killer drones", as well as missiles and shells.
Drone strikes on a residential area of Kyiv region hit upper floors of two student dormitories in the city of Rzhyshchiv. Four people were killed and an 11-year-old was among the wounded, rescue services said. A three-storey school building was also hit.
Meanwhile officials said a person had died and 25 more were injured in the south-eastern city of Zaporizhzhia, which was also hit.
In a tweet, Mr Zelensky said residential areas in Zaporizhzhia were being targeted and it could not become "just another day" in Ukraine or the rest of the world.
Ukraine's military said 16 of the 21 drones launched on Wednesday from the Bryansk region of Russia, north of Ukraine's border, were shot down.
Referring to Chinese President Xi Jinping's departure from Russia hours earlier, the Ukrainian leader said that every time "someone tries to hear the word 'peace' in Moscow", another order was given to launch attacks.
On Tuesday, President Vladimir Putin said that many provisions of a 12-point Chinese peace plan "can be taken as the basis for [the] settling of the conflict in Ukraine, whenever the West and Kyiv are ready for it".
The plan makes no specific proposals and does not call explicitly for Russian forces to leave Ukraine's sovereign territory.
Separately, officials in Russian-annexed Crimea said a Ukrainian drone attack on their fleet were repulsed.
Explosions were reported by residents in the port city of Sevastopol.
The head of Russia's occupation authority Mikhail Razvozhaev said three "objects" targeting the Black Sea Fleet had been destroyed and Russian warships were not damaged.
There was no comment from Ukraine's military, which said earlier this week it had destroyed missiles destined for the fleet at a rail hub in Dzhankoi in northern Crimea.