CHICAGO (CBS) — Police were investigating early Tuesday after receiving reports of shots fired near the Chicago Riverwalk downtown.

Around 3:30 a.m., police received a call of shots fired on Lower Wacker Drive near Wabash Avenue.

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Investigators determined a large group of males had been firing shots. Several shell casings were spotted on the ground near the Riverwalk.

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No injuries were reported. A silver car might have been involved in the shooting.

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No one was in custody early Tuesday. Area Central Detectives were investigating.