A Russian “guided air bomb” hit a blood transfusion center in northeast Ukraine Saturday night, killing two people and injuring four, Ukrainian officials said.

“This war crime alone says everything about Russian aggression,” Ukrainian President Volodymyr Zelenskyy said in Telegram post, alongside a picture of a building engulfed in flames.

He said that a “guided air bomb” had hit the blood transfusion center in the northeastern city of Kupiansk.

In a separate post on his own Telegram channel, regional Gov. Oleh Syniehubov said initial reports suggested two men had died and another four were injured in the “large scale fire.”

Houses and farm buildings were also damaged, he said, adding that residential housing and other agricultural buildings had also been struck in nearby villages.

NBC News could not independently verify these claims, and Russia has repeatedly denied deliberately targeting civilians in what it calls its “special military operation” in Ukraine, although Western leaders and Ukraine’s armed forces estimate thousands of people, both military members and civilians, have been killed, and millions more displaced.

The city of Kupiansk and its outlying settlements are in Kharkiv, which were seized by Russian troops in the early days of Moscow’s full-scale invasion of Ukraine in February 2022.

The area was liberated during a Ukrainian counteroffensive in September but has since come under heavy shelling and attacks.