It happened at the corner of Rising Sun and Cottman avenues at 3 p.m., Philadelphia Police Commissioner Kevin Bethel told reporters Wednesday evening.
Three suspects were sitting in a parked car near a Dunkin Donuts before opening fire, according to Bethel.
"At some point when the bus is pulling up and the kids are converging to get on the bus, three individuals exit that vehicle and then discharges multiple times," he said.
No arrests have been made as of 7 p.m. Wednesday.
Over 30 shots were fired, striking victims between the ages of 15 and 17, authorities said. All were students of Northeast High School.
One 16-year-old victim who was shot nine times in the torso is in critical condition, police said. The others were taken to area hospitals in stable condition.
Philadelphia Mayor Cherelle Parker noted that 11 juveniles have been shot across the city in the last three days.
"Enough is enough," she told reporters.
"This is what's extremely important to me as mayor of the city, that the people of the city know that we will not be held hostage," Parker said.
Commissioner Bethel said the department will "be ramping up our resources significantly" in light of the recent shootings.
Philadelphia school Superintendent Tony Watlington said trained crisis professionals will be made available for NEHS students beginning tomorrow.
Anyone with information is urged to call 215-686-8477 or 911.
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