Henderson Upper Campus Principal Patricia Lampron was taken to a hospital after being assaulted, authorities said.
When Boston police arrived, they found her unconscious, on the ground, being tended to by staff members.
Her injuries, while serious, aren’t considered life-threatening. Sources told CBS Boston the 61-year-old suffered broken ribs and a head injury.
Another staff member was struck as well, but it wasn’t clear what injuries were sustained.
A 16-year-old female suspect was arrested and will appear in Dorchester Juvenile Court on assault and battery charges.
There was no early word on what set off the incident.
It was witnessed by many students, staff and parents.
“This violent behavior will not be tolerated,” Superintendent Brenda Cassellius said in a statement. “The health, safety and well-being of our students and staff is our top priority at Boston Public Schools. I am personally involved and am ensuring we are taking immediate and swift action.”
Cassellius said the decision to cancel school Thursday was made out of utmost caution.
“This incident is disturbing and completely unacceptable,” Cassellius said. “We want to be clear: Violence of any kind is not tolerated and will not be tolerated in the Boston Public Schools.”
Students in grades 2-12 attend the Upper Campus of the Henderson School.
The Boston Public Schools crisis team and other support staff will be available to students and teachers when they return to the classroom on Friday.
