Police have fired baton rounds and deployed water cannon on rioters as violence linked to the Union Flag row flared in east Belfast again.
The fifth successive night of trouble in the area came after hundreds of loyalists staged a largely peaceful protest at Belfast City Hall.
The disorder erupted as around 250 demonstrators from east Belfast returned from the city centre past a volatile community interface at the republican Short Strand.
Police said a number of missiles were thrown at the protesters from the Short Strand area, where around 70 youths had gathered.
The trouble soon spiralled from there as police moved up the adjacent Newtownards Road to separate rival factions.
Officers were attacked with petrol bombs, paint bombs, fireworks and heavy masonry while rioters damaged vehicles with hatchets and sledge hammers.
Protesters constructed a barricade in the middle of the road and set it on fire.
Police also received reports of an attempted car hi-jacking in the nearby Templemore Avenue area and attempted lorry hi-jacking in the Albertbridge Road area.
Police deployed water cannon and five baton rounds were fired. Calm was eventually restored.
The earlier demonstration at Belfast City Hall came as the council met for the first time since its controversial decision to limit the flying of the flag on the roof.
Loyalist protests have been continuing across Northern Ireland since early December in response to the vote by Belfast councillors to only fly the flag above City Hall on designated days instead of all year round.
The first of these days is this Wednesday, when the flag will be raised to mark the birthday of the Duchess of Cambridge.
More than 60 police officers have been injured in flag-related unrest in the last five weeks, with around 100 people arrested.
On Monday night, two males and two females were arrested in east Belfast for riot and public order offences.
Earlier in the day Northern Ireland Chief Constable Matt Baggott claimed senior members of the paramilitary Ulster Volunteer Force (UVF) had been orchestrating the street violence in east Belfast.
Mr Baggott said there was no evidence that the organisation's leadership endorsed their actions.
He also made a direct appeal to protesters on the streets of Belfast to stop demonstrations or ensure they are peaceful.
In a news conference at Police Service of Northern Ireland headquarters in Belfast, Mr Baggott said: "I would like everybody involved in these protests now to take a step back.
"My ambition is that the protests will come to an end, although you appreciate that the police are not in control of that.
"But if not, at the very least those involved in the protests should be off the road, not causing obstruction, absolutely condemning violence and ensuring that these young people are not involved.
"And that requires a concerted effort from politicians and those who have put themselves up as organisers acting together and from parents and responsible members of the community.
"At the moment there is a lack of control, which for me is very worrying."
Loyalists involved in the protests have claimed police have been too heavy-handed in their approach.
The violence in east Belfast has also been fuelled by protests taking place close to an interface where loyalist and nationalist residents live on opposite sides of a peace wall.
Loyalists support Northern Ireland remaining as part of the UK, but nationalists generally support a united Ireland.
The protests bring large numbers of people onto the streets in the area where relations between residents are traditionally tense.
A forum has been set up to try to give those involved in the protests another way to voice their concerns other than demonstrating.
It has been acknowledged that the flag protests have unearthed deeper concerns within loyalist communities.
People living in these areas have said they feel they have been left behind by the peace process and are not benefiting from the political changes since the Good Friday Agreement.