The two factions blamed each other for the violence

A Protestant man was shot in the leg and petrol bombs were thrown at police, who retaliated with an estimated 40 plastic baton rounds.

A police spokesman said there were reports of several houses coming under attack in the Whitewell and Cavehill areas.

Police and troops moved in to separate rival nationalist and loyalist factions in all the different areas, and themselves came under attack.

Petrol bombs and fireworks were thrown and one police officer was struck on the head by a breeze block thrown from the roof of a shop.

'Aggressive' police

Both sides blamed each other for the trouble which erupted in the Ardoyne, Crumlin Road, Duncairn Gardens and Whitewell areas.

DUP MP Nigel Dodds said nationalists were behind the trouble.

Fireworks were thrown at police and troops

"It's is clear, given the pattern of events, with violence happening across four or five areas virtually simultaneously that there was an element among nationalists and republicans who clearly wanted to take out their frustrations on the streets," he said.

"It is lamentable as a result of that police men and civilians have been injured."

However, Sinn Fein councillor Margaret McClenaghan said the trouble at Ardoyne began when a loyalist mob from nearby Twadell Avenue threw bricks and bottles at nationalists.

She accused the police of firing plastic baton rounds at Catholics who attempted to defend themselves against the loyalist onslaught.

"The attitude of the police and British Army is not helping. They are very aggressive against nationalists," she said.

But Progressive Unionist Party Assembly member Billy Hutchinson blamed republicans for starting the trouble.

And he accused the security forces of turning on loyalists.

"After the Rangers Celtic match, they came out of the bars at Ardoyne and attacked loyalists.

"Every time Celtic get beat there are riots here," he said.

Iron bars

"There is a lot of anger because the police and army cracked people's heads open and fired plastic bullets," he added.

Sinn Fein councillor Gerard Brophy said the trouble at North Queen Street began when a group of 12 Protestant men attacked nationalist homes with iron bars.

He blamed the Ulster Defence Association for orchestrating the violence.

Accusing the police and Army of heavy-handedness, he said a youth had been knocked down by a Land Rover during the confusion.

A police spokesman said there were also reports of a gun attack on police in the Ardoyne area.

A police car there was damaged but there were no reports of injuries.

So far, detectives said they had identified 15 people involved in the trouble, and expect to identify more.