Nearly a dozen Salt Lake police officers were called to East High School Friday afternoon to help break-up a large fight.

The school had just finished an assembly and students were free to go for the day, said East High principal Paul Sagers.

"How it inititated was students who haven't gone here for a long time ... confronted our freshmen kids," Sagers said.

A fist-fight ensued, involving about four East students and four of what Sagers called "trespassers." A school resource officer saw a total of about 50 people, including bystanders and others who weren't part of the fight, and immediately called for backup, said Salt Lake police detective Roger Williams.

"It was definitely gang related," Sagers said. "Luckily, everyone was right in the hall after the assembly and it was contained right off the bat," he said.

Police responding to the scene finished clearing the school and got all the students out of the building. Students were told to leave and come back in about a half hour to visit lockers or participate in scheduled extra-curricular activities, Sagers said.

Detectives could not confirm Friday afternoon whether the fight was gang related. Authorities said six people were being detained for questioning.

Investigators were reviewing school surveilance tape Friday afternoon to determine what evidence to turn over to prosecutors for possible charges.

No weapons were involved, he said, and no serious injuries were reported.

"It was real contained, real quickly," Sagers said.