This was reported by the head of Mykolaiv Regional Military Administration Vitaliy Kim.
He wrote that a hit was recorded in the city and reported the number of victims according to preliminary information.
It is not yet known what kind of weapon was used in the attack, but the Ukrainian Air Force has previously warned of a missile threat in the Mykolaiv region.
Later, the Southern Defense Forces clarified that the strike was carried out with ballistic weapons. They also reported an increase in the number of casualties.
"According to preliminary information, 4 civilians were killed and 5 were injured. There is damage to residential buildings and cars in the private sector. Damage to industrial facilities was also reported. The circumstances are being clarified," the statement said.
On the morning of April 12, Kim informed that a 37-year-old man who had been seriously injured in the attack had died in hospital.