Police braced for fresh violence
Police were bracing themselves for another night of violence after a protest by loyalists against new restrictions on flying the Union flag passed peacefully.
The picket outside City Hall in Belfast ended after about an hour with a rendition of God Save the Queen.
Two tricolours were burned amid chants and jeers while protesters sang a number of sectarian songs.
The Police Service of Northern Ireland (PSNI) said protesters had dispersed, but there were pockets of disorder in east Belfast and a section of the Newtownards Road was closed.
"A police officer has been injured and taken to hospital," a PSNI spokeswoman added.
On Friday night, eight police officers were injured and more than a dozen people arrested - including a 13-year-old boy - during clashes between loyalists and riot police.
PSNI Assistant Chief Constable Will Kerr said loyalist paramilitaries had been orchestrating some of the violence seen in the past 24 hours.
"Violence has serious and unwanted consequences for us all and we will robustly investigate all incidents," he said. "I am urging everyone to be calm, take a step back and think about how this violence is affecting not just their own communities but the whole of Northern Ireland."
About 2,000 people attended the demonstration in Belfast city centre. As protesters did a lap of the City Hall, some who used scarves to hide their faces banged on the back gates which were reinforced with metal sheets after Monday night's disorder.
Up to 20 PSNI armoured Landrovers were lined up on either side of City Hall while officers in full riot gear with dogs could be seen in the courtyard of the Edwardian building.