"We believe it's definitely some sort of shootout because we found 35 spent shell casings from semi-automatic weapons," Philadelphia Poice Chief Inspector Scott Small said.
Investigators said the shooting happened shortly after 3:15 a.m. near the area where South 8th Street intersects Wolf Street and West Moyamensing Avenue.
Officers on patrol heard gunshots and responded to the scene within seconds, according to Chief Inspector Small.
The arriving officers discovered two men, who appeared to be in their 20s, unresponsive on South 8th Street.
Police found a gun next to each of the victims.
Philadelphia Police Chief Inspector Scott Small provides details on deadly shooting
Medics pronounced one victim dead at the scene after he was shot multiple times in the chest; the other victim was pronounced dead at the hospital after suffering a single gunshot to the shoulder.
Investigators said they found shell casings in four separate locations around 8th and Wolf streets.
They said at least four unattended vehicles were struck by bullets.
Small said when police arrived at the scene, they saw a vehicle leaving the area.
"So they followed that vehicle. Police pulled that vehicle over about a mile away at 3rd (Street) and Oregon (Avenue)," Small said.
Police said three males were inside the vehicle, as well as a gun in plain sight.
The three individuals, identified as persons of interest, were taken into custody for questioning.
Investigators are working to match guns, bullets and shell casings.