In Belfast, a crowd of Loyalists, mostly teenagers, pelted police with petrol bombs and fireworks for a sixth night in a row.
However officers did not resort to water cannon and plastic baton rounds as was the case on Monday.
The continuing violence as been condemned by community leaders and politicians.
“The way forward is not through throwing bricks and petrol bombs at police officers,” said Northern Ireland Secretary Theresa Villiers. “Those who think they are furthering the cause of the Union flag by using violent tactics are wholly misconceived. The way forward is through talking and through the political leadership of Northern Ireland and engaging in a dialogue.”
Riots began last month after a vote by mostly nationalist pro-Irish councillors to limit the century-old tradition of flying the British Union flag from Belfast City Hall.
More than 100 people have been arrested in scenes not witnessed since the 1998 peace deal.
So far militant nationalists have not responded violently to the flag protests.