Two drones struck a civilian building in central Sumy, regional military administration head Oleh Hryhorov said. A rescue operation began after the attack.
It later emerged that the building hit was a kindergarten. A female security guard at the facility was killed in the attack, while two other employees, aged 52 and 53, were injured.
The body of the woman was found at the site of the strike, Hryhorov said. According to city military administration head Serhii Kryvosheenko, one of the injured women is in hospital in moderate condition, while the other received treatment in hospital after being examined.
The authorities said there were no children in the kindergarten at the moment of the strike.
Nearby residential buildings were also damaged, with windows and balcony frames blown out.