Campus police were called to disperse a large, "unruly" crowd that gathered for the quarterly "undie run" at UCLA, police said.
Dozens of police officers, including LAPD, responded to the area around 1 a.m. to help break up the crowd, according to the UCLA Police Department.
About 8,000 runners joined the traditional run just after midnight.
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Police said there was an issue with people coming to the run who were not UCLA students
Several medical-related issues were reported about who were drunk and falling down, police said.
No officers were injured.
No one was arrested in connection with the unrest, police said.
Oleevia Woo and Corey Arvin contributed to this report.