Ukraine's president says 31,000 soldiers have been killed since Russia's full-scale invasion began, APA reports citing BBC.
Volodymyr Zelenskyy said he would not give the number of wounded as that would help Russian military planning.
Typically, Ukrainian officials do not make public the number of servicepeople killed in the war.
It comes after the defense minister said half of all Western aid for Ukraine has been delayed, costing lives and territory.
"At the moment, commitment does not constitute delivery," Rustam Umerov said in a televised address on Sunday.
Ukraine is currently experiencing a variety of setbacks in its mission to drive Russia from its territory.
Mr.Umerov said that the lack of supplies put Ukraine at a further disadvantage "in the mathematics of war".
"We do everything possible and impossible but without timely supply it harms us," he said.