Russia once again subjected Ukraine to massive drone attacks on Saturday night.
According to the Ukrainian air force, the areas affected included Kiev, the Vinnytsia region to the south-west of the capital, the north-eastern Ukrainian border region of Sumy, the central region of Cherkasy, the southern city of Mykolaiv and the port city of Odessa on the Black Sea.
Explosions were reportedly heard across much of the country. There had previously been an air alert in numerous areas.
There was initially no information about damage or casualties.
Explosions were also reported in the Russian-occupied Black Sea peninsula of Crimea.
The air defence in Sevastopol had repelled a missile attack, Crimea's Russian-appointed Governor Mikhail Razvozhayev said on Telegram in the early hours of Sunday.
The governor cited the Sevastopol rescue service as saying there were initially no reports of damage to civilian infrastructure had been reported, said Razvozhayev.
The information provided by both sides could not initially be independently verified.
Russia launched its full-scale invasion of Ukraine more than two years ago.