Russian forces launched drone attacks on Odesa, Mykolaiv and Kherson oblasts overnight on July 18, according to the Southern Operational Command update.
Several waves of drone attacks have been recorded.
Mykolaiv Mayor Oleksandr Sienkevych said via his official Telegram channel that a fire was reported in the city following the attack. First responders were called to the scene, according to the mayor. He did not provide any further information.
Numerous explosions were also reported in the southern port city of Odesa, while regional Governor Oleh Kiper urged residents to remain in shelters.
Southern Ukraine, especially Mykolaiv and Kherson oblasts, frequently come under Russian strikes.