At least 18 people were shot, including four killed, as gunfire erupted in several places around Ohio's Cincinnati city overnight, authorities said in different news outlets.

After 12:30 am on Sunday in the Avondale neighborhood and found 21-year-old Antonio Blair with gunshot wounds, police said in an official statement. He was taken to University Hospital and died there, they said. Three other gunshot victims were also taken to the hospital, an Associated Press report added.

At about 2:15 am, officers responded to a report of gunfire in the Over-the-Rhine neighborhood where 10 people were shot, police said. One died at the scene and another at the University of Cincinnati Medical Center; they were identified in a statement as 34-year-old Robert Rogers and 30-year-old Jaquiez Grant.

News outlets reported the shootings took place within 60 to 90 minutes of each other, but Assistant Police Chief Paul Neudigate told reporters that they "seem to be separate independent incidents but horrific and tragic."

 "One extremely violent night in the city of Cincinnati. Looking at possibly 17 victims, up to four that could be fatal at this time. Why? That's going to be the question," Neudigate had said before the fourth shooting was announced.

Cincinnati's police chief later Sunday called the level of violence "unacceptable."

"I am calling on all citizens of this great city to say enough is enough! We must not sit by silently and say we can't do anything to end gun violence," Chief Eliot Isaac said in a statement. "We all have a moral obligation to stop the violence and stop the killing in our communities."

Police said the department would shift officers from other assignments to beef up the number of uniformed officers in the affected communities and would call on federal prosecutors and the Bureau of Alcohol, Tobacco, Firearms and Explosives "to focus on repeat shooters and aggressively bring illegal gun charges."

Mayor John Cranley called it "senseless gun violence that ruined lives and will cause immeasurable suffering" at a time the city was facing "unprecedented circumstances and challenges" in fighting crime during the Covid-19 pandemic. He said the city has seen an uptick as people gather in private homes and public places when the bars close.

He stressed, however, that those firing were responsible for the shootings — which he called "attempted or actual murder" — and vowed to bring them to justice, the report added.