Children as young as 13 and 14 were among those arrested at a riot in Belfast on Friday night.
Police said 15 officers were injured after a protest descended into violence in Sandy Row.
Four were unable to report for duty as a result of their injuries.
PSNI Belfast District Commander Chief Superintendent Simon Walls said: “Police were in attendance in Sandy Row last evening, (Friday, April 2) when a small local protest quickly developed into an attack on police officers.
“A total of fifteen officers were injured after being subjected to a sustained attack by rioters who threw a number of objects at police, including heavy masonry, metal rods, fireworks and manhole covers. Their injuries include burns, head and leg injuries. As a result we now have four officers who cannot report for duty as a result of their injuries.”
Chief Superintendent Walls urged anyone with influence in a communities to calm tensions.
He said: “The majority of those involved in the disorder last night were young people. In fact two of the eight people arrested were two young boys aged 13 and 14.
“By engaging in this type of behaviour they are not only risking their safety, they are also risking their futures.
“I understand there are significant tensions and unease in some communities. My job is to keep people safe and I would ask that anyone who has any influence in communities – whether parents, guardians, community or elected representatives – please, use that influence to ensure young people are kept safe and away from harm.
“Local communities deserve to live in safe and peaceful areas, free from rioting and violence.”
