A file photo shows a crime scene blocked off by the Chicago Police Department. (WTTW News)

Two people were killed and seven others were wounded Tuesday night following an argument that escalated into an exchange of gunfire in Washington Park, police said.

Chicago police Deputy Chief Fred Melean said there was a “personal altercation” between two groups in the park in the 500 block of East 51st Street at around 7:45 p.m Tuesday before “multiple shots were fired.”

It was initially reported that one person — a 43-year-old man who suffered a gunshot wound to the back of the head — had died and six more were wounded. A second victim — a 20-year-old man who’d been shot multiple times — later died, and police added two more victims who they said suffered graze wounds.

The ages of the other victims range from 22 years old to 46 years old, and police said all were hospitalized in good condition.

Melean said police believe all the victims were members of those two groups that got into the argument.

As least 43 shell casings were found at the scene, CPD Chief of Detectives Brendan Deenihan said Wednesday, but no weapons have been recovered

Police believe this was likely a gang-related incident, and that individuals from both sides fired shots at each other. But Police Superintendent David Brown it’s unclear who exactly fired at who.

No one has been arrested as of Wednesday morning, and police are seeking the community's help to generate more leads.

“We believe that people have information on who the shooters were,” Deenihan said, adding that anyone with information can submit anonymous tips to police at cpdtip.com or by calling 833-408-0069.

Contact Matt Masterson: @ByMattMasterson | [email protected] | (773) 509-5431