Russia launched a massive wave of missiles and drones against Ukraine on Wednesday, killing at least 20 people, including children, and damaging industrial and energy facilities.

Ukrainian President Volodymyr Zelenskiy called the attack one of Russia’s “most vile strikes” and said it involved about 70 missiles, many of them ballistic.

The heaviest casualties occurred in Pryluky in the Chernihiv region, where a missile destroyed a five-story residential building, killing at least 14 people, including four children.

Zelenskiy said the attack coincided with Russian President Vladimir Putin’s birthday and described the destruction as a deliberate and demonstrative strike, Reuters has reported.

About 50 people were wounded, including seven children, as rescuers searched through the collapsed building for survivors and victims.