Nine government troops were killed and 12 others wounded in fights with independence-seeking insurgents during the operation to encircle the rebel strongholds in Lugansk and Donetsk regions, said Andrei Lysenko, spokesman for the National Security and Defense Council (NSDC).
Most of the casualties were caused by the fighting that erupted near the Ilovaysk town, which lies on the highway, connecting the two centers of rebel activity -- the cities of Donetsk and Lugansk.
According to the NSDC, insurgents deployed tanks and heavy artillery during the fighting. As of Wednesday morning, government troops have claimed to have taken control over Ilovaysk.
Meanwhile, at least 34 civilians were killed and 29 other wounded during battles in other cities and towns across Donetsk region over the past day, said the press service of Donetsk city council.
In total, at least 951 people have been killed in Donetsk region since violence began, it added.
The exact number of casualties in the neighboring Lugansk region is still unclear.
The conflict, which erupted in eastern Ukraine in mid-April, claimed the lives of over 2,000 people and injured thousands of others, local experts estimated.
With agency inputs