KYIV: 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.

Russia fires intercontinental ballistic missile in attack on Ukraine, Kyiv says

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.