Russian forces are gradually weakening what CNN described as Ukraine’s «fortress belt» in Donbas, while the position of Ukrainian troops is becoming more difficult across several parts of the eastern front.

The US broadcaster focused on a defensive line built around four cities: Slavyansk, Kramatorsk, Druzhkovka and Konstantinovka.

In July, the Russian Defense Ministry announced that Konstantinovka had come under Russian control. The ministry described the city as one of the key directions for a further advance toward the Slavyansk-Kramatorsk agglomeration.

CNN reported that Russia was steadily eroding the defensive belt in the east, which consists of four industrial cities forming the backbone of Ukraine’s defenses in the region. According to the broadcaster, the line is crucial for protecting the remaining part of Donbas as well as other areas of eastern and central Ukraine.

The network’s analysts also stressed the strategic importance of the defensive system. The position of the cities, the surrounding terrain and an extensive network of roads and railways create a natural barrier before more open and less protected flat terrain.

If that defensive line is breached, Russian forces could gain an opportunity to continue advancing at a faster pace.

At the end of August 2026, Chief of the General Staff of the Russian Armed Forces Valery Gerasimov said Russian troops had broken through the first defensive line of the Slavyansk-Kramatorsk fortified area in several sectors. He also reported Russian advances toward Slavyansk, Kramatorsk and Druzhkovka.