Four officers were taken to hospital while others were treated at the scene of severe disorder, at the junction of Royal Avenue and North Street in the city centre, on Friday night. One officer remained in hospital on Saturday morning.
A number of parked vehicles were set on fire in the North Street and Shankill Road areas.
Police responded to the disorder with two water cannon and 26 baton rounds in a bid to restore calm.
Seven people were arrested in connection with riotous behaviour, disorderly behaviour and hijacking.
Trouble flared in Belfast city centre after hundreds of loyalist protestors gathered ahead of the republican rally.
The parade route started at Ardoyne Avenue, moving along the Oldpark Road, Rosapenna Street, the Cliftonville Road, through the New Lodge and into the city centre.
But, as the trouble broke out, police sealed off North Queen Street stopping the parade from progressing towards Royal Avenue.
Sporadic violence later broke out in the Peter's Hill area where missiles were thrown from both sides at police lines. Water cannon was used at the bottom of the Shankill Road to keep the crowd apart from the rally, which then moved on towards west Belfast.
Those people had no intention of peaceful protest, they lack self respect and they lack dignity.
PSNI Chief Constable Matt Baggott
On Saturday morning, police revealed that some rioters took to the roof tops of city buildings and houses and tried to set them on fire. The PSNI stressed that the parade was not re-routed by their officers with organisers voluntarily deciding to take another road.
At a specially convened PSNI press conference, Mr Baggott added: "I know that 99%, if not more, of the population will stand with me in utterly condemning those who scarred the reputation of our beautiful city last night."
He said that without the courage of his officers, lives may have been lost.
"We made arrests last night where we could, you can be assured that many more would follow.
"And if anyone doubts our resolve on this, just think on the 500 or so already arrested and prosecuted or reported since the beginning of the disturbances this year," he added.
"There's plenty of evidence of what happened last night - we're very good at that and I have no doubt whatsoever that custodial sentences will be handed down in the weeks and months that follow.
"The prisons will be bulging, sadly."
The disorder broke out as the city hosted thousands of international visitors attending the World Police and Fire Games.
The Secretary of State for Northern Ireland, Theresa Villiers, described the unrest as "shameful".
"After success for Northern Ireland this summer as host to both the G8 and the World Police and Fire Games, disorder on the streets is a hugely regrettable step backwards," Ms Villers said.
There were no winners last night, but I know there will be losers amongst the retailers and communities directly affected.
Justice Minister David Ford
Justice Minister David Ford said the violence was "wrong".
"Some individuals and groups may not agree with determinations from the Parades Commission, but they do have the weight of the law behind them," he said.
"Until we come up with an alternative way to deal with contentious parades the police are required to put themselves in the front line to uphold those determinations.
"I am confident that over the coming days and weeks those involved in the violence will be the main losers as the police begin gathering evidence and carrying out arrests," he added.
Reacting to the violence on Friday night, North Belfast DUP MLA Nelson McCausland said: "The march by a dissident republican rabble was designed to provoke a violent loyalist reaction and it succeeded.
"We would appeal for an end to any violence and want to meet urgently with the PSNI and the Secretary of State to discuss the events in Belfast tonight, including the role of the Parades Commission and the policing operation."
What should have been a great week for the city, with thousands of visitors for the World Police & Fire Games, has ended badly and the image of Northern Ireland has been tarnished by violence.
Nelson McCausland, DUP MLA
Sinn Féin's deputy First Minister Martin McGuinness tweeted: "Those responsible for tonight's violence against the police are the combined forces of the UVF & OO in N Belfast."
He later added: "The riot and resulting injuries to (...) police officers by loyalists in Belfast must be strongly condemned and organisers identified."
However, Progressive Unionist Party leader Billy Hutchinson has denied any UVF involvement in the violence.
Speaking to UTV on Saturday morning after a peaceful Apprentice Boys march, he said: "This shows that people can walk down the road. If there's respect, all of this can be resolved.
"I think lots of people need to realise, I mean why can't we do this at any other time?"
He said that being a member of the Orange Order and of the PUP was not a crime.
"I think what Martin McGuinness is talking about is that I work together with the Orange Order.
"What he can't get out of his head is that I'm the leader of the PUP and yes, I'm an ex-combatant in the UVF and yes, I served 16 years.
"I don't make any apologies for that. But, let Martin McGuinness challenge me about that and let Martin McGuinness tell me that I haven't worked hard for the peace process - because I have.
"There is no collusion between the Orange Order and the UVF."
Ulster Unionist Party Leader, Mike Nesbitt MLA said: "The violence witnessed in Belfast last night was wrong and I condemn it all, whoever was responsible, and it certainly did not come from a single group.
"Violence against the police from those belonging to the Protestant Unionist Loyalist community is not only wrong, it is also playing into the hands of Irish Republicanism," he added.
"It removes the focus from the offensive nature of their attempt to re-write history and excuse the terrorism that blighted our country for decades, and still does."
It is time for the DUP to demonstrate political leadership, to go beyond the politics of 'we told you so' and condemn the actions of those who turned their protests against a republican parade into a shameful and violent desecration of Belfast City Centre.
Dr Alasdair McDonnell, SDLP Leader
SDLP Leader Dr Alasdair McDonnell has said the DUP needs to decide whether it backs the rule of law or mob rule.
"The ugly scenes on our streets are an affront to democracy and do not reflect the will of law abiding citizens.
"This was an attack on those who seek to uphold law and order as well as the businesses which are at the very heart of the City and it's economic success.
"The depressing message being beamed around the world is that this place is still in the clutches of a minority who would seek to drag us back to the past"
Policing Board Chair Anne Connolly said: "Such violent behaviour on the streets of Belfast on the back of a successful World Police and Fire Games is shameful, causes disruption to the community and will impact on policing resources.
"I urge those who wish to bring themselves on to our streets in coming days to seek peaceful solutions."