Police arrested nine students inside Frankford High School this morning after a fight broke out among a large group of girls in a second floor hallway, city police said.
One student was cut above her left eye and was being treated at the school by paramedics, police said.
There were no injuries to staff.
Police were not sure how many students were involved.
A teacher, who asked to remain anonymous, said there appeared to be about 50 students congregated in the area of the fight. All security officers were called to the floor over the loudspeaker, the teacher said. Students were hitting the security officers, the teacher said.
"It was just an out of control crowd," the teacher said.
A school district official said he would check into the incident.