Russian strikes killed at least two people in the northeastern Ukrainian city of Sumy, the acting mayor said Friday.
"Several massive explosions occurred in Sumy," Artem Kobzar said in a video message on Telegram, adding that at least two people had died.
He said air defences were still working as of just before 6:00 am local time (0400 GMT) and warned residents to stay away from windows.
The Sumy regional military administration said a residential neighbourhood had been struck by a Russian UAV, adding that rescue operations were underway.
Sumy lies across the border from Russia's Kursk region, where Ukrainian troops captured swathes of territory after launching a major ground offensive in August.
The strikes come a day after Russia fired a new generation intermediate-range missile at Ukraine -- which Putin hinted was capable of unleashing a nuclear payload.
In recent days, Ukraine has fired US and UK-supplied missiles at Russian territory for the first time, escalating already sky-high tensions in the nearly three-year-long conflict.
