Sumy, with a population of around a quarter of a million and located just over 25 kilometers from the Russian border, became a garrison city when Kyiv's forces launched an incursion into Russia in August. Sumy's acting Mayor Artem Kobzar announced three days of mourning for the victims, starting on Monday.

Amid the ongoing Russia-Ukraine war, a Russian commander was killed Friday in the Kursk region by a Ukrainian strike that involved a U.S.-supplied High Mobility Artillery Rocket System (HIMARS), according to a report from the pro-Russian Telegram account Dosye Shpiona.

Russia's defence ministry has said the two ballistic missiles it fired at the Ukrainian city of Sumy yesterday were aimed at a meeting of Ukrainian military officers.