Rioters in Northern Ireland fired shots and hurled petrol bombs at police during a third night of violence blamed on republicans opposed to the British province's peace process.

Young children were among hundreds who took to the streets of Ardoyne in north Belfast overnight as violence continued following the peak of the marching season, a traditional flashpoint for sectarian tensions.

First Minister Peter Robinson and his deputy Martin McGuinness, who have appealed for calm, are to meet Northern Ireland's police chief Matt Baggott later today to discuss the ongoing tensions.

Authorities are blaming a small group of troublemakers for the unrest, with Baggott describing trouble earlier this week as "recreational rioting with a sinister edge." Witnesses have also told of how children got involved.

"I was directly confronted by a nine-year-old last night," Father Gary Donegan, a local priest, told BBC radio, saying he had "physically pulled stones out of children's hands."

"At one stage, it looked like the Milan catwalk," Donegan added. "It was ridiculous. There were girls out with little parasols... it was a bit like a Eurodisney theme park for rioting."

Local councillor Gerard McCabe, of republicans Sinn Fein, said the culprits were "an anti-social group hell bent on torturing the community."

There were reports of four to six shots being fired at police in mainly Catholic Ardoyne which police are investigating, while rioters also threw stones and missiles.

Police deployed a water cannon in response but reported no new injuries to officers, although 82 have been hurt in clashes on previous days, including a female officer who had a concrete block dropped on her.

The disturbances come at the height of Northern Ireland's marching season, a traditional flashpoint in the troubled province's history.

Unrest often flares as Protestant marchers -- in favour of continued British rule of the province -- pass through areas mainly populated by Catholics, who are generally opposed to rule from London.

In the most violent riots of the past few days on Monday, dissident republicans threw petrol bombs and concrete slabs at Protestant Orangemen and their police escort as they marched through Ardoyne.

Monday was July 12, which is the climax of the marching calendar and sees Protestants mark Prince William of Orange's victory over the Catholic King James II at the Battle of the Boyne in 1690.

Despite the relative calm in Northern Ireland since the 1998 peace accords, violence frequently breaks out around July 12 as Catholics try to prevent the marches from going ahead.

The province's First Minister Peter Robinson and his deputy Martin McGuinness both criticised the violence Tuesday, saying it was out of keeping with modern-day Northern Ireland.

"I am disgusted at the outright thuggery and vandalism that has taken place over the course of the last 48 hours," said Robinson, leader of the Democratic Unionists, Northern Ireland's largest Protestant party.

"There is no excuse and no place for violence in civilised society... We must keep our entire focus on defeating those who would seek through violence and destruction to drag us back."

McGuinness, of Catholic republicans Sinn Fein, said: "Our experience demonstrates that the way to deal with any disputes or contention is through dialogue and agreement."

The leaders' response came after Northern Ireland police's number two Alistair Finlay criticised their grip on events and urged them to speak out against the violence, in a rare challenge.