Police said a teen has been arrested after a fight between two students at Haverhill High School on Thursday morning.
School resource officers broke up a fight between two girls at the school around 11:30 a.m. One of them was arrested.
It happened during one of the school's lunch periods. Cell phone video shows other students gathered around and some cheering the fight on.
No injuries were reported, police said.
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Parents were informed with a robocall and an email.
In that letter to parents, Haverhill High School Principal Jason Meland said there was an incident during first lunch.
"The situation is under control and students are safe," he said. "The female student in question has been removed by the Haverhill Police."
For the remainder of the school day, he said the school operated under hold-in-place protocol, meaning students attended their classes as scheduled but were restricted from freely moving about the hallways without a pass.
Meland said parents will be given further information later on Thursday.
A parent who spoke with NBC10 Boston and NECN, who did not want to be identified, said her daughter said there was a weapon involved. That has not been confirmed by police or officials.
"It's shocking but it’s not the first time it's happened at this school or other schools… it's unfortunate that parents strike out a the schools but the schools can only do so much - parents need to parent their kids," she said.
Because the incident involved underage students, police said no further information is being released.