FOUR police officers have been injured in another night of loyalist rioting linked to the Union flag row in Northern Ireland.
One of the officers required hospital treatment as some protests again turned ugly.
The most serious disorder was witnessed in Carrickfergus and the Rathcoole area of Newtownabbey, both on the northern outskirts of Belfast.
Police were attacked with 33 petrol bombs, as well as masonry and other missiles. Vehicles were set on fire.
Officers fired five baton rounds and deployed water cannon to restore calm.
Two arrests were made.
A small viable pipe bomb device was found on the Westlink dual carriageway in Belfast but it was unclear whether it was linked to the loyalist disorder.
Around 70 police officers have been injured and more than 100 people arrested in six weeks of trouble since Belfast City Council limited the number of days the Union flag flies over Belfast City Hall.
A Police Service of Northern Ireland (PSNI) spokesman said: "Police will continue to pursue a vigorous evidence gathering operation to bring those involved in the violence to justice."
There were widespread demonstrations across Northern Ireland last night in co-ordinated action dubbed Operation Standstill by organisers. Police said most of the protests were peaceful.
Many roads were blocked off between 6pm and 8pm as protesters again took to the streets to voice their opposition at the flag decision.
But the city centre was not as empty as might have been expected after an online campaign urged people to defy the protests and stage an Operation Sit-in in cafes, pubs and restaurants to give businesses hit by the six-week campaign of street action a much-needed boost to trade.
The Democratic Unionist Party and Progressive Unionist Party have both submitted challenges in Belfast council over the decision to restrict the flying of the flag.
They claim the move contravened its equality policy.
A Belfast City Council spokeswoman said: "The decision to introduce the policy of flying the Union flag at City Hall was taken democratically by elected members at the monthly meeting of Belfast City Council on December 3.
"The council has taken legal advice throughout this process and the decision is in keeping with the outcome of the equality impact assessment that was undertaken in line with the advice of the Equality Commission.
"The designated days agreed are in keeping with those notified by the UK Government's Department of Culture, Media and Sport."
Yesterday, one of Northern Ireland's most senior Protestant ministers called on loyalists to end "intolerable" attacks on police.
Presbyterian Moderator Dr Roy Patton said: "The situation being faced by the police is intolerable and in keeping order on our streets and bringing people before the courts the PSNI must have the full support of all who want to see an end to this violence."
Unionist politicians have tried to find common ground by setting by a forum to consider ways to move beyond demonstrations, but they have insisted it was not a step towards a single unionist party.