The office of the Alliance Party in Carrickfergus was damaged tonight after rioters tried to set it on fire.
The trouble is being linked to a vote in Belfast Council on Monday when Alliance party representatives successfully proposed to limit the flying of the Union Jack over Belfast City Hall.
Police say 1,500 people were involved in a protest in Carrickfergus earlier this evening and afterwards a small group began throwing bottles and bricks.
Police fired a number of baton rounds in an attempt to disperse the crowds and a number of PSNI officers were injured during the clashes.
Four people, two men and two women, were arrested.