Some 2,000 demonstrators rally at City Hall where loyalists torch an Irish tricolour but there were no immediate reports of clashes. Police blame paramilitaries for violence over the flag.

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Eight officers were injured overnight on Friday and 13 people arrested in clashes between loyalists and police. Six officers were injured in the Crumlin Road and Ligoneill Road area of north Belfast and two at Shaftesbury Square in the city centre. Among those arrested was a boy aged 13.

A major security operation was underway on Saturday to prevent trouble at the demonstration in front of Belfast City Hall, which no longer flies the Union Jack every day. A heavy police presence was noticable but the atmosphere was reportedly calm and crowds began to disperse by late afternoon.

Loyalist paramilitaries blamed

PSNI Assistant Chief Constable Will Kerr blamed Loyalist paramilitaries for orchestrating some of the recent violence and warning anyone engaging in criminal activity that they will face "the full rigours of the law."

"Violence has serious and unwanted consequences for us all and we will robustly investigate all incidents," he said, adding that he urged everyone to stay calm and take a step back.

US Secretary of State Hillary Clinton condemned the Belfast violence on a visit on Friday. Her husband played a vital role in ending violence in Northern Ireland in one of the biggest policy triumphs of his administration.

Loyalists oppose restrictions on flying the flag

Loyalists opposed to new restrictions on flying the union flag at Belfast city hall have been holding protests across Northern Ireland all week after the city council voted to fly the union flag on designated days. Police blame paramilitaries for organising some of the recent violence.

Three people - two men, aged 18 and 29, and a 17-year-old boy - were due in court on Saturday.

The council voted to fly the flag on about 20 designated days. Nationalists at Belfast City Council had wanted the union flag taken down altogether, but in the end voted on a compromise from the Alliance party that it would fly on designated days.

Unionists have said they consider the changes regarding the union flag to be an attack on their cultural identity.