Russian troops have entered the city of Slavutych, north of Kyiv -- a move which has sparked protests among hundreds of Ukrainian civilians.
Early Saturday, Oleksandr Pavliuk, head of the Kyiv regional administration, said "the Russian occupiers entered the city of Slavutych and seized the city hospital."
The mayor of Slavutych, Yuri Fomichev, asked residents to come to the city square with Ukrainian symbols to "show their position."
Images and video geolocated by CNN showed a crowd -- possibly several hundred people -- chanting "Slavutych is Ukraine" and "Glory to Ukraine" in the main square. A large Ukrainian flag was unfurled.
The sound of at least three stun grenades, whose origin is unclear, can be heard.
Later, as the crowd moves through the square, several bursts of heavy gunfire can be heard.
Pavliuk also said that "according to the latest information, the mayor Yuri Fomichiv was abducted by invaders."
Late on Friday, the mayor had issued a statement on Facebook saying that: "Our defenders defended bravely and selflessly! But we do not have equal strength! Unfortunately, we have our dead."
Some background: The arrival of Russian forces in Slavutych follows several days of shelling against the city, which is strategically located close to the Dnieper River, about 95 miles (150 kilometers) north of Kyiv and close to the border with Belarus.
According to local officials, the city has been isolated almost since the beginning of the Russian invasion.
Slavutych was built for workers at the Chernobyl nuclear plant after the 1986 disaster left the area uninhabitable.