The Ukrainian city of Kreminna, northwest of Lysychansk, continues to experience heavy fighting as the Russian military keeps renewing its forces there, the head of the Luhansk regional military administration, Serhiy Haidai, said Tuesday.
"The Russian occupation troops managed to build a very powerful defense in a month, even a little more. They are bringing there a huge amount of reserves and equipment. They are constantly renewing their forces," Haidai said.
He said the Russian military had suffered a large number of casualties "but they still bring new [personnel], because they understand that if they lose Kreminna, in principle, the entire line of defense will crumble."
CNN has not been able to verify the number of casualties on the Russian side.
Ukrainian President Volodymyr Zelensky acknowledged on Monday evening that the situation on the frontlines in Bakhmut, Kreminna and other areas in the eastern Donbas region is “difficult, painful” as Russian forces use all resources available to them "to squeeze out at least some progress."
Why Kreminna matters: The town in eastern Ukraine's Luhansk region has been occupied since the spring.
Kreminna lies on a key north-south road from Svatove, which Russian troops had been using to resupply and which became even more important to them after Ukrainian troops took over Kupyansk, a resupply hub to the northwest of Kreminna and Svatove. Losing Kreminna would limit Russia's ability to resupply its troops in the key city of Severodonetsk.
Haidai said the road remained under Ukraine's fire control, which meant there was "no safe and calm way for the occupiers to bring in the equipment or ammunition towards Kreminna using this road," he said.
Ukrainian forces appeared to be on the verge of retaking Kreminna a few weeks ago, but Ukrainian officials said the approaches to the city were difficult because of extensive mining.
"Every meter is difficult, because everything there is mined and they are constantly shelling with large caliber," Haidai said, saying the situation in Kreminna was "radically different from Bakhmut."
"[Russian troops] are trying to shell more powerfully, they have occupied all the forests, they have completely mined everything and no one knows the map of minefields. Therefore, it is very difficult to advance," Haidai said.
The Washington-based Institute for the Study of War, which follows the conflict closely, said information from Russian military bloggers suggests that "Russian forces are pulling troops from various points throughout the theater to fill holes in the Svatove-Kreminna line and compensate for the continued degradation of conventional units."