A gunman opened fire on a crowd of people in Cleveland early Sunday, wounding nine before fleeing the scene.

Officers on duty in the city’s historic Warehouse District responded at about 2:30 a.m. and provided medical aid, Police Sgt. Jennifer Ciaccia said in a Facebook post. The victims were rushed to a local hospital.

Police Chief Wayne Drummond said seven men and two women ages 23 to 38 were struck. One person was seriously wounded and the rest had minor injuries, he said. No fatalities were immediately reported.

At an early-afternoon news conference Sunday, Drummond said officers were patrolling the area before the incident occurred but have not ascertained what led to it.

“We’re not sure what happened,” Drummond said. “We have no information at least right now from our investigators that there was any type of issue or concern or trouble.”

Ciaccia said investigators are reviewing evidence and video and interviewing victims as they try to get information that may lead them to the perpetrator.

The Warehouse District is a popular night spot featuring trendy shops, restaurants, bars and nightclubs.

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How many mass shootings have taken place in 2023?

The shooting rampage is the latest in a series of mass shootings that has made 2023 one of the most violent on record. The Gun Violence Archive says more than 365 mass shootings have taken place so far this year. Gun violence has taken the lives of more than 22,000 Americans in 2023, according to the group.