A Ukrainian presidential aide told the BBC that between 100 and 200 Ukrainian soldiers are killed on the front line every day, the BBC reported.
Mykhaylo Podolyak said Ukraine needed hundreds of Western artillery systems to level the playing field with Russia in the eastern Donbass region.
He also said that Kyiv was not ready to resume peace talks with Moscow.
Ukrainian troops are under constant shelling as Russian forces attempt to take control of all of Donbass.
“Russian forces have launched just about everything non-nuclear onto the front line, including heavy artillery, multiple rocket launch systems and aviation,” Podolyak said.
He reiterated Ukraine’s call for more weapons from the West, saying the “complete lack of parity” between the Russian and Ukrainian armies was the reason for Ukraine’s heavy casualty rate.
“Our requests for artillery are not just a kind of whim…but an objective need with regard to the situation on the battlefield,” he said, adding that Ukraine needed 150 at 300 rocket launchers to match Russia – a much higher. number that it has received so far.
Mr Podolyak also said peace talks could only resume if Russia returned the territory it had won since its February 24 invasion, according to the BBC.
Mr. Podolyak’s suggestion that 100-200 Ukrainian soldiers die every day is higher than previous estimates. On Thursday, Ukrainian Defense Minister Oleksii Reznikov said Ukraine was losing 100 soldiers a day and another 500 were injured.
The different casualty figures are a sign of the difficulty of obtaining accurate battlefield information.
Despite the heavy casualties, Mr. Reznikov claimed that a large number of Russian soldiers are also killed.
“The Kremlin continues to press heavily, stumbles, faces heavy rebuffs and suffers huge casualties,” Reznikov said. “But he still has forces to advance in certain parts of the front.”
Similarly, Luhansk regional governor Sergei Gaidai said Russians were “dying like flies”, but echoed Mr Podolyak’s assertion that Ukraine is facing difficulties with a shortage” catastrophic” artillery.
Russian forces concentrated their assault on the city of Severodonetsk. On Wednesday, Mr Zelensky said the “fate of Donbass was being decided there” and officials said it had been reduced to rubble by intense Russian artillery and missile barrages, reports the BBC.
In addition to frontline fighting, two Britons and a Moroccan who fought for the Ukrainian Armed Forces were sentenced to death on Thursday by an unrecognized court in the so-called Donetsk People’s Republic.
They were found guilty of being mercenaries and of having “acted with a view to the violent seizure of power”.