Russian defenses are "likely brittle" amid the ongoing Ukrainian counteroffensive, the ISW said.
The think tank noted that Russian forces likely lack the reserves to rotate frontline units.
Popov reportedly claimed that he had appealed to his superiors to rotate troops and relieve those who had fought on the frontlines for a long time.
The think tank said that without any reserves to rotate in, Russian forces would have to rely on "already degraded forces" in the event of a Ukrainian breakthrough.
Ukrainian troops train with heavy weapons near the frontline in Zaporizhzhia on April 20, 2023.
Persons:
Ivan Popov, Popov, Muhammed Enes Yildirim, Volodymyr Zelenskyy, Oleksandr Tarnavskyi
Organizations:
Service, Institute for, Russian, Anadolu Agency, Getty Images Ukraine, BBC, Sky
Locations:
Ukraine, Russia, Wall, Silicon, Zaporizhzhia, Ukrainian, Donetsk