Loyalists have thrown bottles and stones at police in a sixth straight night of violence in east Belfast.
The Police Service of Northern Ireland said "calm has now been restored" to the Newtownards Road area and all roads have re-opened to traffic.
Meanwhile, a special meeting of Unionist representatives has been called in a bid to end the violence because of a decision to restrict the flying of the Union flag above City Hall.
It is due to fly again tomorrow to mark the birthday of the Duchess of Cambridge.
Earlier, riot police faced hundreds of masked men in and around the lower Newtownards Road.
Fireworks, rocks, golf balls and petrol bombs were also fired at the police lines.
Northern Ireland First Minister Peter Robinson has confirmed that representatives of the various unionist parties will meet at Stormont on Thursday to discuss the ongoing trouble.
But leaders centrally involved in the protests, who are threatening to take their campaign to the streets of Dublin on Saturday, have pledged they want no part in the discussions.
Minister for Justice Alan Shatter has said gardaí will be prepared for any eventuality on Saturday.
He said that if individuals want to march on the streets of Ireland, in protest or to express a view, they have a democratic right and an entitlement to do so.
The minister said if a march takes place, he hopes the views that are being expressed by those individuals will be allowed to be expressed and that there will not be any untoward incidents.
Mr Shatter said: "I know that the gardaí will undertake any preparation necessary to ensure that if there is an event in Dublin the maximum possible is done to ensure the safety of any individuals who march.
"I would certainly hope other individuals would not opportunistically use this event to create problems on our streets."
There was a fifth consecutive night of rioting in east Belfast last night when nationalists clashed with loyalists who were returning to the area after a demonstration outside Belfast City Hall.
The protest was held as Belfast City Council met for the first time since it made the controversial decision to restrict the flying of the flag.
Most of the violence over the Union flag controversy has involved loyalist crowds attacking the police.
However, as dozens of loyalists were returning to east Belfast after what had been a peaceful demonstration outside the city hall, rows broke out with nationalists from the Short Strand area.
Sectarian songs were sung and the loyalists said the first missiles came from the nationalist side, with the PSNI trying to separate the factions.
Heavy masonry and petrol bombs were fired at the police.
Some of the loyalists battered police vehicles with hatchets and officers used baton rounds or plastic bullets to disperse the crowds.
Elsewhere, some of the sharpest exchanges at the council meeting involved DUP and Sinn Féin councillors whose parties lead the power-sharing government at Stormont.
However, Sinn Féin councillor Tom Hartley reminded councillors that a year ago they had all voted to fund street parties to mark Britain Queen Elizabeth's jubilee celebrations.