Government forces pressed on with an offensive against pro-Russia separatists in eastern Ukraine on Wednesday which it said had inflicted heavy losses on the rebel side.
A spokesman for Kiev's "anti-terrorist operation" said more than 300 rebel fighters had been killed and about 500 wounded in fierce fighting in the past 24 hours in and near the city of Slaviansk, a strategically-located separatist stronghold.
Separatist sources could not immediately be reached to give a casualty toll from Tuesday's fighting, in which government forces used aircraft, helicopters and artillery to try to root out separatists who have controlled Slaviansk since early April.
Describing fighting as "heavy", the government forces spokesman, Vladyslav Seleznyov, said two servicemen had been killed and 45 wounded.
A spokeswoman for the rebels, Stella Khorosheva, said on Tuesday night that the death toll in the town "was rising continuously."
President-elect Petro Poroshenko, who scored a resounding victory in an election on May 25, ordered the resumption of operations by government forces to quell a rebellion by pro-Russian militia across the Russian-speaking east.
The Kiev government says the fighting is fomented by Moscow, which opposes its pro-Western course. Kiev also accuses Russia of letting volunteer fighters cross into Ukraine to fight alongside the rebels. Moscow denies this and is urging Ukraine to end military operations and open dialogue with the separatists.