PHILADELPHIA (CBS) — Philadelphia Police are investigating after they say a 6-year-old girl was shot on Tuesday night.

The shooting took place on the 6300 block of N. Woodstock St.

Police say the girl suffered a gunshot wound under her left arm. Police arrived on the scene shortly before 7:00 p.m.

Upon their arrival, police found her unresponsive.

Authorities say the girl was taken to Einstein Hospital and was listed in critical condition. Her injuries required emergency surgery.

“The bullet went under her left armpit area, which is very bad spot to be hit by gunfire, the left side of your chest where the heart is located.”

She was later transferred to St. Christopher’s Hospital, where she is now in recovery.

Police say there were at least 21 shots fired from two different weapons. They say the 6-year-old was playing on the front steps of her home when she was hit.

Authorities believe that she was struck by a stray bullet. Police believe at least one semi-automatic gun was used.

“When someone gets hit with a stray bullet, and they are innocent, that is of particular concern to us,” police say.

The description of the shooter is a male wearing a white t-shirt. He fled in an unknown direction.

Police found several businesses and homes in the area with surveillance cameras, in addition to a crime camera located a few blocks away.

No word on a motive for the shooting.