Two men and two women have been detained for rioting and public order offences following the disorder which broke out on the lower Newtownards Road after a flag protest in the city centre passed off peacefully on Monday night.
Police said violence erupted after a crowd of around 70 nationalist youths from the nearby Short Strand area hurled missiles at the loyalist protestors returning from the demonstration, some of whom chanted sectarian abuse.
"A number of missiles were thrown from the Short Strand area as the crowd of approximately 250 protestors returned to East Belfast," a PSNI statement said.
"Additional police officers responded to support Neighbourhood officers who were already on the ground in the Short Strand in order to deal with a crowd of around 70, mainly youths, that had rapidly gathered."
Police later discharged five baton rounds and used water cannon after they came under attack from loyalist rioters.
Fireworks, bricks and petrol bombs as well as other missiles were thrown at officers in the area and vehicles were attacked with hatchets and sledge hammers.
Barricades were set on fire on the lower Newtownards Road.
An attempted car hijacking in the Templemore Avenue area and an attempted lorry hijacking in the Albertbridge Road area have been reported.
The Newtownards Road and Albertbridge Road have now reopened to traffic.
I don’t want young people being dragged back into a world where their only aspiration is violence.
PSNI Chief Constable Matt Baggott
PUP leader Billy Hutchinson told UTV Live Tonight: "Once again tonight there were attacks from Short Strand and the police didn't prevent those from happening."
He said he would be seeking more information from police.
"I want to ask the chief constable for a security briefing in terms of who is involved in the violence in Short Strand. This violence came about more than once this week.
"Is this being carried out by republican paramilitaries? Of what shade?" Mr Hutchinson asked.
Alex Maskey, Sinn Féin MLA for South Belfast, described the latest violence as "very unfortunate".
"Because we have the street disorder and heavy violence in that area over the last number of days, it's bound to spill over and I want to see all of us appealing for calm heads and mature heads."
This was the fifth consecutive night of trouble in east Belfast, which PSNI Chief Constable Matt Baggott believes is being orchestrated by senior members of the UVF.
"I fear that we will have a generation of young people for whom violence becomes the norm again. And that brings enormous sadness," Mr Baggott told UTV's Sharon O'Neill.
"We need to have a generation who are benefitting from the peace."
Meanwhile disorder also broke out in Dundonald where police have been attacked with petrol bombs, fireworks and other missiles.
A car was also set on fire at nearby Bute Park.
Police maintained a presence in the Upper Newtownards Road area after calm was restored on Monday night.
All roads that were closed to traffic have reopened following the disturbances.
Earlier there was a heavy police presence in the city centre as around 400 loyalist protestors gathered at City Hall. Following the demonstration, they walked around the building to police lines and back to the front before dispersing.
Donegall Square East, South and West were closed to traffic for a time but have now reopened.
The protest coincided with Belfast City Council's first full meeting since it passed a motion to restrict the flying of the Union Flag at City Hall.
At a council meeting in December, a majority of representatives voted to reduce the number of days the flag is flown.
It was followed by weeks of protests and rioting in which 62 police officers have been injured.
Around 100 people were arrested and 73 charged in the last month.
The issue of flag was not listed on Monday night's council agenda, however councillors discussed it.