An Alliance party office has been set alight in Carrickfergus, while bottles and missiles were thrown at police during disturbances in the town centre on Wednesday evening.
Up to 1,600 people gathered in the Irish Gate roundabout area to protest over the new Union flag policy at Belfast City Hall earlier this week.
“The majority of the crowd dispersed however there are a number of people still in the area,” said a PSNI spokesperson.
“Bottles and other missiles have been thrown at police but there are no reports of any injuries at this stage.
“Police are in the area and are liaising with local community representatives in an effort to restore calm.”
Police later said a number of officers were injured.
Stewart Dickson MLA has confirmed his office had been set on fire laying the blame solely at the feet of the DUP and UUP.
Along with his party Leader David Ford, the MLA for East Antrim has requested the Assembly be recalled and has demanded answers from his Unionist colleagues.
Stewart Dickson MLA said: “This is an outright attack on Democracy and cannot be allowed to continue. The police have informed me my office is on fire and all I can do is wait to see the extent of the damage.
“This campaign of intimidation against the Alliance Party cannot be allowed to continue.
“The blame lies firmly with the two Unionist parties who distributed bogus leaflets across loyalist areas in Belfast ahead of the December meeting of Belfast City Council. They cannot expect to whip up Unionist tensions and encourage people to protest and then wipe their hands of any involvement.
“The DUP and UUP have also failed to convincingly condemn both the violence that occurred in Belfast on Monday night and the threats and attacks against the Alliance Party.
“They must be held accountable for their actions and it is for this reason that David Ford MLA and I have already contacted the speaker of the Assembly to request the Assembly is recalled this week.
“The Alliance Party will not continue to be bullied and intimidated by Unionists.”
DUP East Antrim MP Sammy Wilson said: “People are entitled to peacefully protest but there is absolutely no justification for the carnage which has been caused in Carrickfergus this evening. I unreservedly condemn the violence.
Those involved do a disservice to the flag they claim to defend. Today, in the House of Commons, several MPs backed the Union Flag being flown from City Hall, however this criminal behaviour undermines and distracts from the argument.
“I urge those involved to step back from this criminal activity and channel their energies through democratic politics.”
TUV Leader Jim Allister said the violence and attack on the Alliance office was utterly wrong.
“The great political and constitutional wrong done to the Unionist majority in Northern Ireland by the Alliance Party delivering the Sinn Fein agenda of denuding the capital city of its daily expression of its Britishness does not warrant or justify violence, rather it calls for a sustained political response.
“Whatever the level of alienation and anger, aping the violence of republicanism is not the way forward, even when the evident rewarding of the IRA has set a dangerous, but destructive template, which unionists must not follow ,” he added.