Chattanooga Police Chief Celeste Murphy said in a press conference on Sunday that two victims died from gunshot injuries and a third died after being struck by a vehicle in the shooting, which took place at around 2:45 a.m.
In addition, 14 people were injured by gunfire and three more were hurt as they were hit by vehicles while attempting to flee the scene.
Murphy added that 16 of the victims are adults and one is a juvenile.
Several of the victims remained in critical condition.
Investigators believe that more than one person opened fire during the shooting, but Murphy said there is no immediate danger to the public.
She added the incident was not related to the Riverbend Festival, an annual music festival taking place in the city over the weekend, or another shooting that took place three miles away on the other side of downtown Chattanooga in which three people sustained non-life-threatening injuries.