Ukraine’s President-elect Petro Poroshenko has vowed to punish the “bandits” responsible for shooting down an army helicopter on Thursday.
It was hit by a surface-to-air missile near the town of Sloviansk in the east of the country.
Twelve soldiers, including a general, died in the attack, which has been attributed to pro-Russian separatists.
Sloviansk has seen fierce fighting between the rebels and Ukraine’s army.
In Donetsk, where fighting on Monday to control the airport resulted in 40 deaths among the rebels, families buried their loved ones.
Chechen fighters are believed to have joined the pro-Russian fighters in the east, although the Chechen President Ramzan Kadyrov denies having sent any troops.
There is still no news of four OSCE observers who disappeared earlier in the week.