A Russian-guided aerial bomb hit a blood transfusion centre in the town of Kupiansk, in the eastern Kharkiv region late on Saturday, Ukrainian President Volodymyr Zelensky said.
“There are dead and wounded,” he said on his Telegram channel.
“Rescuers are extinguishing the fire. This war crime alone says everything about Russian aggression.”
Kupiansk is a railway hub fewer than 10 miles from the front and a couple dozen miles from the Russian border.
The strike came shortly after Mr Zelensky said Russian missiles had hit a facility of the Ukrainian aeronautics group Motor Sich, a maker of plane and helicopter engines and other components.
It is one of several companies requisitioned by the government since Moscow’s invasion. The Motor Sich site is near Khmelnytskyi in western Ukraine, around 190 miles southwest of Kyiv.
The region, home to a major Ukrainian airbase, has been regularly targeted by Russian strikes in recent months.
Both attacks came just hours after Kyiv hit a Russian tanker in the Kerch Strait.