Fourteen more police officers have been injured after another night of violence in parts of Northern Ireland.
It brings the total number of police officers injured in the past week to 88.
Three 14-year-old boys were arrested during the disorder and have been released pending further enquiries.
The trouble happened around the loyalist Tiger’s Bay and nationalist New Lodge areas of north Belfast, as well as Coleraine, County Londonderry.
During the disorder, a burning car was rammed against a police Land Rover and missiles were thrown in the Tiger’s Bay area, with bins also set alight.
Petrol bombs, bottles and masonry were thrown at police in the New Lodge.
Ch Insp Darren Fox said the “disgraceful scenes” in Belfast started at about 17:00 BST, and lasted until about 01:00 in parts of the city including Duncairn Gardens and North Queen Street.
“This was reckless and dangerous criminal behaviour which resulted in a number of our officers sustaining injury,” he said.
Ch Insp Fox said most of the injuries had been minor, although one officer had been knocked unconscious and required hospital treatment.
“Residents in these areas, or indeed anywhere, do not want or deserve to experience the fear many of them will have felt in recent nights,” he said.
He added evidence was being gathered and “those identified will face the full rigour of the law”.
Friday night marked the 12th night of violence in Northern Ireland in recent days.
The previous evening, police deployed water cannon for the first time in six years after coming under attack in Belfast.
Saturday marks the 23rd anniversary of the signing of the Good Friday Agreement in 1998.
Reporter Kevin Sharkey in Belfast
The worst of Friday night’s violence was in the Tiger’s Bay area where there was sustained rioting against the police for several hours.
Police were attacked with petrol bombs, stones and other missiles and two officers were seen being helped back to their vehicles after being injured.
In the neighbouring New Lodge area, the police were also attacked, but the rioting in this area was more sporadic.
The police were attacked in New Lodge early in the evening but there was a lengthy lull before the attacks on police lines intensified there at about 23:00 BST.
The police created a buffer zone, several hundred metres in length, to keep the two communities from goading and attacking each other.
But rioters in both communities continued to attack the police lines which were keeping them apart.
There was a big police operation in the two areas throughout the evening and into the night.
During the sustained violence in the Tiger’s Bay area, the police brought in dogs to assist their operation against the rioters.
In Coleraine, petrol bombs were thrown at police officers during three hours of disorder.
Ch Supt Davy Beck said the “senseless disorder” had left people in a residential area “petrified in their homes”.
Police came under attack in the Atlantic Road area of the County Londonderry town, after about 40 people, many of them masked teenagers, set up a road block and set it on fire.
When police responded, two petrol bombs were thrown at them, and a further five petrol bombs were thrown when additional officers arrived in the area.
Police said masonry and other missiles were also thrown at police, with some damage to police vehicles. No police officers were injured on this occasion.
Order was restored to the area by about 22:45 BST.
Ch Supt Beck appealed to “parents, guardians and community leaders to use their influence” to prevent a repeat of “such ugly scenes”.
“Such reckless criminal activity has only served to harm the local community by those who deliberately chose to engage in such disorder,” he said.
Caoimhe Archibald, a Sinn Féin MLA for the East Londonderry constituency, said she had spoken to police about the disturbances.
“There is no place for this destructive and senseless behaviour,” she said.
SDLP MLA Cara Hunter said the “reckless violence” did not “reflect the warm and welcoming people of Coleraine”.
Independent MLA and former justice minister Claire Sugden said the violence in Coleraine had been “nothing more than anti-social behaviour and attention seeking – which is sad in itself”.
“Clearly, bad behaviour of a few and not representative of Coleraine.”