Zelenskyy made the alarming claim in his nightly video address, adding that he believes the Russians may soon damage the Zaporizhzhia nuclear power plant and blame Ukraine.
The coming winter may provide Ukraine with more opportunities to retake land from Russia, Western military analysts say. It will also bring a change in battlefield tactics.
While Ukraine's counteroffensive this month was hailed as stunning by military observers, Ukrainian troops tell NPR that Russian forces put up stiff resistance in parts of the Kharkiv region.
Villagers describe allegations of abuse and officials say they found a torture chamber in Kozacha Lopan, in the Kharkiv region, which Russian forces invaded and took over at the start of the war.
The southern Mykolaiv region has seen targeted strikes, leading Ukrainian officials to round up hundreds of people suspected of leaking information to the Russians.
Ukrainian forces liberated the town of Balakliia in a swift counteroffensive against Russia in the east, where retreating Russian troops left behind tanks, captives and an untold number of casualties.
