Kharkiv, Ukraine’s second-largest city, is “under missile attack”, its mayor has said.
Ihor Terekhov made his comment not long after regional governor Oleh Syniehubov said at least five Russian drones had struck the northeastern city late on Thursday.
Mr Terekhov said the city’s Osnovyanskyi district had been hit, triggering a fire.
It is unclear whether there have been casualties.
Fabrice Deprez, a journalist reporting from Ukraine, said on X he had “lost count of the number of explosions shaking Kharkiv right now – a dozen or more in the past hour”.
An air raid alert lasted more than 16-and-a-half hours, public broadcaster Suspilne said – the longest alert since Russia invaded Ukraine in February 2022.
Residents are advised to stay in shelters.
Kharkiv has been a frequent target of Russian attacks in recent weeks.
President Volodymyr Zelenskyy visited the city earlier on Thursday to try to boost morale.
In recent days, Moscow has advanced several kilometres into the north of the Kharkiv region.