The gunshots rang out just before 2:30 p.m. on Seward Avenue in the Soundview section.
Police say the girl was not the intended target and was with a small group of other people when the man came up and opened fire.
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She was standing outside a building when she heard shots, felt pain and ran inside. That's when police say she looked down and noticed that her knee was bleeding.
She was rushed to Jacobi Hospital and is expected to survive.
The gunman fled the scene, and so far, no arrests have been made.
The investigation is ongoing, and anyone with information in regard to this incident is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782).
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