Fresh trouble broke out in North Belfast last night when crowds clashed in the Limestone Road area for the third night running.
At least three police officers were injured when they moved in to separate the nationalist and loyalist groups.
A Police Service of Northern Ireland spokesman said petrol bombs, bricks, bottles and other missiles including fireworks were hurled by the factions - both at each other and the police.
Two officers have suffered leg injuries and the other has head injuries.
In republican west Belfast a fireman was injured after being lured to a fire in the Grosvenor Road area.
Police said the fire service was called four times to fires in a derelict bungalow in Cullingtree Road and were each time attacked by youths hurling bricks and bottles.
Two fire engines were put out of action with shattered windscreens. One broke around an officer, who was cut by flying glass.
PA