Media playback is unsupported on your device Media caption Northern Ireland Chief Constable Matt Baggott condemned the rioters.

The number of police officers injured during loyalist protests against a republican parade in central Belfast is 56.

The police fired 26 plastic bullets and made eight arrests on Friday evening amid sustained rioting in Royal Avenue.

Northern Ireland's Chief Constable Matt Baggott described the violence as "mindless anarchy" and "thuggery".

He praised his officers, saying they had put their lives on the line to protect the rule of law.

"I want to, as ever, commend my colleagues for their immense courage last night. I have no doubt whatsoever that they prevented that anarchy from spreading and without that courage, many lives may well have been lost," Mr Baggott said.

Officers hospitalised

He added that those who attacked police had "no intention of peaceful protest".

Bricks and fireworks were thrown at officers, and they were also attacked with scaffolding poles and paving stones ripped from the city's streets.

A PSNI spokeswoman said four of the injured officers needed hospital treatment and one of them remained in hospital.

Image caption Dozens of police officers were injured during loyalist protests against a republican parade

In addition to plastic bullets, police also used water cannon and dogs during the disorder.

The eight people arrested on Friday night were detained on suspicion of offences including riotous behaviour and disorderly behaviour. The police said a number of people have now been charged.

Mr Baggott said: "We made arrests last night where we could, you can be assured that many more will follow."

He added: "I have no doubt whatsoever that significant custodial sentences will be handed down in the weeks and months that follow. The prisons will be bulging, sadly."

Shops damaged

Northern Ireland Secretary Theresa Villiers described the violence and attacks on police as "shameful".

She said what had happened was a "hugely regrettable step backwards" after Northern Ireland's recent successes at hosting the G8 summit and World Police and Fire Games.

The trouble began when loyalists staged a demonstration in the city centre, against a republican parade that was due to pass along Royal Avenue, one of Belfast's main shopping districts.

Media playback is unsupported on your device Media caption Theresa Villiers MP: "It is outrageous that police officers were attacked."

The protesters attacked the police with bricks and bottles as they waited for the parade to arrive.

Police said they came under heavy and sustained attack by crowds "intent on creating disorder".

A number of parked vehicles were set on fire in the nearby North Street area and a number of shops and a pub were damaged during the violence.

'Heavy-handed'

Officers also said they had reports that two members of the public had been injured.

Some loyalists accused the police of being heavy-handed.

The commander in charge of the policing operation, ACC George Hamilton, said significant numbers of people began to gather in Royal Avenue at about 17:30 BST on Friday.

"There was absolutely no organisation, no coordination and no leadership around any of those protests. We saw numbers swell to around 1,200 people and it was evident that many of them had violent intent.

"There was no attempt whatsoever that we could see of any organised or coordinated protest activity in line with that which had been notified to the Parades Commission."

ACC Hamilton said police stopped the republican marchers in North Queen Street, while officers "faced huge personal risk" trying to clear protesters from Royal Avenue to make it passable for the parade.

However, he said that after a 25 minute delay the parade organisers decided to avoid Royal Avenue and take a different route towards Carrick Hill, Millfield and into west Belfast.

"The police did not reroute the parade away from Royal Avenue and in fact we were within minutes of having Royal Avenue cleared to allow the parade to go through," ACC Hamilton said.

Major operation

The parade and the protesters later confronted each other about 100 metres apart and what the police have described as serious disorder took place in the Carrick Hill, Peter's Hill and Millfield areas, just north of the city centre.

The parade then passed into west Belfast after protesters were pushed back towards the Shankill area.

Police put in place a major operation ahead of the parade, involving hundreds of officers and dozens of vehicles.

The march, which started in north Belfast, marked the introduction of internment in 1971.

The Parades Commission had given permission for six loyalist protests against the parade. Numbers were restricted at four of them.