A blood transfusion centre was targeted as Moscow unleashed a massive air strike on western Ukraine, following through on its promise to retaliate for a Ukrainian attack on a Russian tanker.
Russian and Ukrainian shelling across the country on Sunday killed at least six people, officials said.
Separately, Moscow's second-largest airport briefly suspended flights early on Sunday following a foiled drone attack near the Russian capital.
Ukraine's air force said Russia launched 70 attack drones and missiles, including cruise missiles from aircraft over the Caspian Sea and Iranian-made, Shahed-136/131 strike UAVs.
Ukrainian President Volodymyr Zelenskyy said that a guided bomb had hit a blood transfusion centre in the area's Kupyan district on Saturday.
A fire broke out at the centre following the attack, he added.
"This war crime alone says everything about Russian aggression," Zelenskyy wrote on social media.
"Defeating terrorists is a matter of honour for everyone who values life."
Zelenskyy said the facilities of aircraft engine manufacturer Motor Sich in the Zaporizhzhia region had also come under attack.
The Russian barrage came after a Ukrainian drone attack on a Russian tanker in the Black Sea near Crimea late on Friday.
Ukraine also struck a major Russian port with drones earlier the same day.
Russian Foreign Ministry spokeswoman Maria Zakharova condemned what she called a Ukrainian "terrorist attack" on a civilian vessel in the Kerch Strait.
Nerve centre for Russian fleet targeted in missile strike
Sign up here to receive our daily newsletters and breaking news alerts, sent straight to your inbox.
