PRESS ASSOCIATION -- Twenty-two police officers have been injured during rioting in Northern Ireland.
Baton rounds were fired and water cannon used in parts of west Belfast after petrol bombs, stones and bricks were launched at police lines.
Four wounded officers were taken to hospital, but none of their injuries were life-threatening, the Police Service of Northern Ireland (PSNI) said.
A bus was hijacked and driven at a police cordon, but crashed a short distance away, according to the force. A fire service appliance was attacked by missile-throwing youths while attending a blaze in west Belfast and ambulance crews were also targeted.
The trouble happened on the night before the Twelfth of July celebrations by Orangemen, during which tens of thousands of members of the loyal orders will walk the streets to commemorate the 1690 Battle of the Boyne victory of a Protestant over a Catholic monarch.
Riots broke out in the nationalist areas of Broadway, Old Park and North Queen Street in the west of the city late last night and continued through the early hours. More than 40 petrol bombs were thrown.
Police used water cannon and fired baton rounds to try to disperse crowds of between 100 and 200 people who began throwing stones and missiles at police lines in the Broadway area of the city. A total of 51 rounds were used.
The Northern Ireland Fire and Rescue Service (NIFRS) said it received 180 calls up to 1am, a 65% increase on last year. At the busiest time, the service was taking a call every 75 seconds, with most within the Greater Belfast area.
PSNI assistant chief constable Dave Jones praised colleagues for their professionalism in containing the violence: "We would appeal for everyone to do everything that they can to help ensure all areas are peaceful over the next 48 hours. Violence does not need to be inevitable."
The largest parade will be in Belfast, where some city centre department stores are planning to open. The Orange Order leadership insists the parades are a unique opportunity to showcase their history and heritage and they draw many overseas visitors.