Six apartments were destroyed and 36 others damaged, Odesa Governor Oleh Kiper confirmed. Footage released by emergency services shows children, women, and elderly residents being evacuated as flames tore through the multistorey block.
Kiper said two children, aged six and nine, were hospitalised for smoke inhalation.
Meanwhile, in Kharkiv, an earlier drone attack on Wednesday morning killed one person and injured four, damaging homes and civilian infrastructure.