Russian troop build-up threatens city seen as key to seizing Ukraine's Donbas

AI Summary

The article reports on a Russian troop buildup near Kostyantynivka, a city strategically important for controlling Ukraine's Donbas region. If Russian forces capture this city, it would facilitate further advances into Ukraine's eastern strongholds.

If Kostyantynivka falls, Russian forces would be able push towards Ukraine's last remaining strongholds in the east.