A police presence was maintained in the Donegal Pass area of south Belfast overnight following earlier disturbances involving rival factions.
It is understood clashes between loyalists and nationalists broke out after flags had been put up to celebrate a local Gaelic football team reaching a championship final.
A PSNI spokesman said the area was calm by early today and that the crowds had dispersed.
At the height of last night's clashes, rival factions fought with each other, the police were attacked and large lines of traffic were diverted.
Near loyalist estates, petrol bombs were thrown into a car park used by police officers at Donegal Pass beside Shaftsbury Square.
The previous night, when GAA supporters put up the flags along the lower Ormeau Road, it is thought that loyalists linked to a paramilitary organisation then intervened to remove them.
Last night groups of local youths began stoning each other. At one stage hundreds of youths were involved in the violence as police were trying to restore calm.
Community representatives on both sides also worked to stop the violence.
