Fears are growing that "disaffected criminal elements" are encouraging young people to orchestrate violence in Northern Ireland.
Disorder has broken out on the streets again, despite appeals for calm.
A car was set alight in Sperrin Park in the Waterside area of Londonderry, while there were also reports of violent incidents in Carrickfergus, near Belfast on Monday night.
Both locations have been the scene of serious unrest among the loyalist communities in recent days.
Former DUP MP Emma Little-Pengelly, now a special adviser to First Minister Arlene Foster, urged those involved in the incidents in Carrickfergus to stop.
She tweeted: "Emotions can run high and frustrations deep, but injury, arrest and prosecution will blight your life forever.
"We believe in the rule of law, break it and there are rightful consequences. Get home, be safe and make your genuine concerns heard in democratic and non-violent ways."
In Carrickfergus, a crowd of young people gathered in the North Road area and lit a fire in the middle of the road.
Petrol bombs were sporadically thrown at police, according to witnesses.
A gang of around 20 youths were spotted at the site of an enflamed car in Sperrin Park.
PSNI Chief Superintendent Davy Beck said the attacks were "clearly orchestrated".
He added: "I believe there’s a small group of disaffected criminal elements that are clearly involved in influencing young people, and I would appeal to young people in those areas not to allow this to happen.
"I think it’s also fair to say there’s probably no coincidence to this.
"We have been successful in that area in respect on some of these criminal gangs.
"So I think that this perhaps has been a reaction from some of those people who are involved in criminality."
Throughout Monday afternoon, masked loyalist bands marched through the streets in towns across the region, including Portadown, Ballymena and Markethill.
The PSNI is investigating those marches, which appear not to have been notified to the Parades Commission.
It follows a turbulent week of events in Northern Ireland, as loyalist tensions simmered over into violence.
Five police officers sustained injuries after being pelted with petrol bombs and masonry in Newtownabbey and Carrickfergus on Sunday night.
Petrol bombs were also thrown at PSNI officers and bins and pallets set on fire in disturbing scenes in Belfast and Derry in recent days.
It brings the total number of police injured in incidents in Londonderry and Belfast over the Easter weekend to 32.
Superintendent Beck said police stand ready for another night of unrest, but urged community leaders to put a stop to it.
"What concerns me most are the young people who are being suckered in to this type of behaviour," said the officer.
"So again I would appeal to parents to think about where their young people are, think about who they’re with.
"And try and have a conversation with them and encourage them not to get involved, not to get sucked in and not to be used in this way.
"Because effectively, that’s what’s happening. They’re being used by other elements within the community."
Tensions have soared within the loyalist community in recent months over post-Brexit trading arrangements, which it is claimed have created barriers between Northern Ireland and the rest of the UK.
Anger ramped up further last week following a controversial decision not to prosecute 24 Sinn Fein politicians for attending a large-scale republican funeral during COVID-19 restrictions.
All the main unionist parties have demanded the resignation of PSNI Chief Constable Simon Byrne, claiming he has lost the confidence of their community.
Meanwhile in Co Antrim, a recent series of drug seizures against the South East Antrim UDA – a renegade faction of the main grouping – has caused particular ill-feeling towards police.
The faction is believed to have been behind disturbances in Newtownabbey on Saturday.
Chief Supt Davy urged those with issues around policing to go through the proper channels and not to take to the streets.
He said: "There’s no justification for taking these actions out on the street. If you have concerns about policing, you can take those local PCSP (Policing & Community Safety Partnership), you can take them to the Policing Board, you can take them to the Police Ombudsman.
"There are mechanisms to deal with these issues. It doesn’t have to be on the street.
"It doesn’t have to affect the rest of your life. Please stop."