Children as young as seven or eight were involved in rioting at a dissident republican Easter commemoration.
The trouble in Londonderry on Monday raised the spectre of another generation of children in Northern Ireland becoming embroiled in violence.
In scenes reminiscent of the height of the Troubles, children of primary school age and young teenagers used bricks, bottles and stones to attack a moving convoy of PSNI Land Rovers near Derry's City Cemetery.
The attacks occurred at the Iniscarin Crescent entrance to the cemetery as a crowd of around 200, including men in paramilitary uniform, gathered for the 32 County Sovereignty Movement's annual wreath-laying ceremony and rally.
The youths, some wearing balaclavas or scarves to obscure their faces, showed no fear as they ran up to kick the slow-moving vehicles and thump the Perspex windows and side panels.
In one incident, a boy of around 10 managed to tear the wing mirror off one of the armoured vehicles.
Police said the child violence was "a sad indictment" of the organisers and participants.
Officers had read out warnings that the gathering was illegal from inside one of the convoy vehicles as it did several laps of a roundabout. But these warnings went unheeded or unheard amid the shouts of youths and the barrage of missiles.
One such broadcast was also interrupted when the passenger door of a Land Rover was flung open by a youth.
The violent scenes broke out before the Easter commemoration got under way on Monday afternoon.
Hundreds of people turned up for what the PSNI on Monday night claimed was "a small-scale event".
The trouble started at around 2pm when a number of parked police Land Rovers were forced to move off after coming under attack before the more widespread rioting broke out.
Violence also flared briefly during the ceremony itself, which was held at a republican memorial statue of Cuchulainn near the top of the cemetery.
As the Irish Proclamation was read out, a police Land Rover was spotted parked in a residential street which looks down on the cemetery.
A police officer was witnessed filming the ceremony. But he was forced to retreat to the vehicle when a petrol bomb landed beside him.
The police vehicle left the area after it came under a barrage of bricks and missiles.
Despite the episodes on Monday, no one was injured and there had been no arrests as of Monday night.
A PSNI spokesman said they would now begin an investigation into events at the rally.
He said: "Police will be making further inquiries following an illegal parade which took place as part of a small-scale event in the City Cemetery this afternoon.
"Officers issued two verbal warnings to those taking part in the illegal procession.
"While the event passed off without incident, it was extremely concerning to see children, some of whom looked to be under the age of 10, throwing stones at police vehicles. It is a sad indictment on those who organised and were in attendance that this was allowed to happen."