Officials have appealed for calm after up to 50 police officers were injured in sectarian riots in north Belfast.
The area witnessed hours of rioting on Sunday night with the Police Service of Northern Ireland forced to deploy water cannon.
Their officers were attacked with fireworks, petrol bombs, and bricks as loyalists protesting over a republican parade attacked police in the Carlisle Circus and Antrim Road areas.
Four officers were hospitalizedwith various injuries while at least 43 other officers were treated at the scene for various minor injuries.
A 17-year-old male was arrested on suspicion of riotous behaviour.
PSNI Chief Supt George Clarke said: “I am both angry and sad that my officers have been subjected to such significant attack.
“They showed tremendous courage in the face of enduring violence.”
The trouble broke out after a large crowd congregated between the Belfast Orange Hall and Carlisle Circus for a lawful parade. Police had received no notification of a protest.
Chief Supt Clarke added: “People will be held to account for their actions.
I am urging all individuals and communities affected by recent events to take a step back. Violence has serious and unwanted consequences for us all.
“We must work harder at finding solutions through talking and accommodation. We cannot continue to see the lives of our community and our police officers put at such risk.
“Every hour of disorder in Northern Ireland not only puts lives at risk, it also reduces confidence in our community and wastes huge amounts of money that could be better spent on schools and hospitals. Violence cannot be a solution.”