A nasty brawl broke out at preschool graduation in California reportedly over a single cap and gown, leaving at least one parent injured and the young graduates wailing.

The fight broke out at Lenicia B. Weemes Elementary School in Los Angeles on June 7 and an unidentified parent posted the video on YouTube this week.

"This all started because my son's teacher was so unorganized," the parent wrote below the video. "Basically because of budget issues all the kids had to share a cap and gown for pictures. One of the moms in the video was basically taking over and the other one didn't like it and told her something about it."

In the grainy video, a crowd of women can be seen shoving each other, throwing punches and shouting. Children can be heard screaming and at one point, a woman shouts, "Get the kids out! Get the kids out!"

The children had just returned to the classroom that morning from their "culmination ceremony" in the auditorium. The classroom was set up for the children to take photographs wearing a cap and gown, according to the school.

"The sad part was that there was an older lady that got pushed and she actually hit her head on a bookshelf and I rushed to help her but when this other mom rushed in to help us the angry women actually attacked the other mom," the parent witness wrote.

The school's Principal Lynn Brown sent a letter home to parents regarding the incident.

"I am saddened to report that a few parents began arguing which resulted in a parent being assaulted and her personal property taken," Brown wrote. "Through the fast actions of school staff the proper authorities were called and the incident was contained to the classroom and main hallway. The parent thankfully, sustained minor injuries."

"It is unfortunate that adults chose to resolve a conflict in this way in front of our youngest boys and girls," she continued. "Parents can use this incident as an opportunity to talk to children about solving conflicts the Peace First way, non-violently. Counseling is available if you or your child may need it."

The L.A. School Police is investigating the incident and "why it happened, what the situation was," Monica Carazo, spokeswoman for the L.A. Unified School District, told ABCNews.com.

Carazo said that one person suffered a minor cut on her lip, but no one else was injured.

As for the children, Carazo said, "I think they were more scared, as you can hear in the video."

(Image credit: EAG News.org/ABC News)