Fresh trouble broke out in North Belfast last night when rival 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 rival nationalist and loyalist groups.
A Police Service 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 are understood to have suffered leg injuries and the other head injuries.
Meanwhile 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 out four times to fires started in a derelict bungalow in Cullingtree Road, and each time they came under attack from youths hurling bricks and bottles.
Two fire engines were put out of action with shattered windscreens, the second of which broke around the injured officer, who was cut by flying glass.