Twenty-nine police officers were injured on Saturday during the 40th day of protests over the removal of Union flag at the City Hall.
Loyalists and nationalists started rioting at the sectarian interface by Short Strand, in East Belfast.
After the rioting subsided in the evening, it erupted again after 9pm with loyalists attacking police with bricks, stones and missiles by Castlereagh Street.
Police used water cannon to push rioters away from interface.