Rioting has flared tonight in a number of flashpoint areas of north Belfast.
Police and troops moved in to separate rival nationalist and unionist factions and there were reports of a number of plastic baton rounds being fired.
Several officers have been taken to hospital with injuries, a police spokesman said.
Both sides blamed each other for the trouble which erupted in the Ardoyne, Duncairn Gardens and Whitewell areas.
Petrol bombs and fireworks were thrown by angry crowds in the Ardoyne.
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 v Celtic match, they came out of the bars at Ardoyne and attacked loyalists.
‘‘Every time Celtic get beat there are riots here,’’ he said.
Mr Hutchinson dismissed as ‘‘nonsense’’ claims that loyalists caused the disturbances.
‘‘There is a lot of anger because the police and army cracked people’s heads opened and fired plastic bullets,’’ he added.