There were further clashes between loyalist and nationalist youths in Belfast last night.
In the Ardoyne area of north Belfast, stones and petrol bombs were thrown by the two sides. Extra police were drafted in to keep the factions apart.
In the Short Strand area, in the east of the city, a stand-off took place between about 50 youths.
Police said last night the area was "peaceful" after the intervention of community representatives.
Gangs of youths clashed during riots in the Ardoyne area on Sunday night.
On Saturday night too, nationalists and loyalists clashed during eight hours of rioting in Cluan Place and Clandeboye Gardens in the eastern Belfast.
It is thought it may have been sparked by the Rangers-Celtic match in Glasgow on Saturday afternoon.
Bottles, bricks and bolts were thrown. One person was taken to hospital with a head injury.