Officers responded to the 3000 block of Cottman Avenue around 5:45 p.m. Sunday.
At the scene, police found a 16-year-old who had been stabbed in the back.
The teen was taken to Jefferson Torresdale Hospital where he was placed in stable condition.
Police say the suspect in this incident is another 16-year-old boy.
The suspect was described as being tall and wearing all-black clothing with white sneakers.
No arrests have been made and no weapons were recovered.
There is no word yet on the motive behind the attack.
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