Police attended to disturbances in the Holyland area of Belfast in the early hours of Friday morning.
Police said they attended reports of anti-social behaviour in the Agincourt Avenue area just before 2am to find "large crowds partying, singing, and generally causing a disturbance".
"It seems that various house parties had extended to the street," a PSNI statement said.
One witness described the incident as a "riot" with around 100 young people "chanting, dancing on cars, lighting fires" and blocking the road.
"Officers spoke to many of the individuals and managed to disperse the crowds," the police statement continued.
"Two males were arrested on suspicion of a number of offences, including disorderly behaviour. They remain in custody at this time, assisting with enquiries."
Police appealed to those responsible to "think about the consequences of their actions and to consider the impact of ending up with a criminal record, which has all sorts of consequences".
Anyone with information is asked to contact 101, quoting reference number 111 of 26/06/20.
Information can also be provided to Crimestoppers anonymously on 0800 555 111 or online at www.crimestoppers-uk.org.