The first incident happened around 8 p.m. on the 3100 block of Mercer Street.
Investigators said they found Jonathan Salas-Kane, 16, on the sidewalk with at least one gunshot wound to the chest.
He was rushed to Temple University Hospital and pronounced dead soon after, according to police.
"Where police found him lying half on the sidewalk and half in the parking lane, we did not find any ballistic evidence, no spent shell casings, so we're not certain if the shooting took place there or not or possibly a revolver was used because we didn't find any ballistic evidence at this time," said Chief Inspector Scott Small of the Philadelphia Police Department.
Hours later, around 10:30 p.m., police said an 18-year-old was shot in the arm on the 4200 block of North Penn Street. The teen is listed in stable condition at an area hospital.
READ MORE: Philadelphia officers in 12th district lead peace walk as shootings continue to rise
And earlier in the day, police said a 12-year-old boy was shot in the arm. He is currently hospitalized in stable condition.
No arrests have been made in connection with these shootings.
"I'm scared for my nieces and nephews," said Deborah Stevenson of South Philadelphia. "Somebody is ripped from you. Oh my God, it's just a feeling that nobody wants to go through."
The 12th police district, in Southwest Philadelphia, held a virtual "Call for Peace" with community leaders on Tuesday.
"Trying to think outside of the box. Come up with new ways to reduce the violence," said Capt. Drissel.
The talk focused on positive programs for young people and brainstormed ways to reach more.
"We have to be consistent with this. We can have a walk, we can have a march, but if we're not engaged with the community consistently, we're going to have to keep coming back," said Mark Harrell, co-chair of the Police District Advisory Council.
Investigators are still looking for the shooters in each case. Anyone with any information is asked to call police at 215-686-TIPS.
According to data provided by the City of Philadelphia, over 1,400 people have been shot this year in the city. To date, 331 people have died by homicide.