There are reports of a large number of explosions in the Ukrainian capital, Kyiv, and air raid sirens have been sounding, APA reports citing BBC.
In video on social media, air defence systems can be seen shooting down suspected Russian missiles.
Government messages warned people to keep away from windows as debris from intercepted missiles fell from the sky.
City mayor Vitali Klitschko said some rocket debris had fallen in central districts, including on the city's zoo.
There are reports of injuries.
The complex attack, which used both drones and missiles, was described as being "exceptional in its density" by one Kyiv official.
Serhiy Popko, head of the Ukrainian capital's military administration, described the barrage as being the "maximum number of attack missiles in the shortest period of time".
"According to preliminary information, the vast majority of enemy targets in the airspace of Kyiv were detected and destroyed," he added.