A total of 55 RUC officers were reported to be injured in last night's rioting in the Ardoyne area of Belfast which lasted over five hours.
At least 15 cars and other vehicles were hijacked and set on fire during the disturbances - the worst seen in the area for many years.
Water cannons and repeated rounds of plastic bullets were used by the RUC which resulted in more than 10 people being injured, according to Sinn Fein.
The rioting erupted as police escorted an Orange Order march passing up the Crumlin Road bordering loyalist and nationalist areas. Police attempted to clear demonstrators off the streets when the violence quickly escalated at around 8.45 p.m. One RUC officer was seriously injured when he was struck by a missile.
By midnight, according to the RUC, 19 officers were hospitalised including two who were set on fire by petrol bombs. RUC assistant chief constable Alan McQuillan said the violence had been "quiet clearly orchestrated". Police estimated at least 100 petrol bombs were thrown at their lines.
Earlier, on nationalist Estoril Park hundreds of people gathered as youths drove a stolen Nissan Micra and a Belfast City Council vehicle up to a barricade.
At 9.25 p.m. police Land Rovers vehicles were attacked with petrol bombs from a shop roof in Ardoyne. One petrol bomb entered the grounds of Ardoyne ambulance depot as loyalists gathered at the end of Twadell Avenue at Ardoyne round about.
By 10 p.m. running battles between police and nationalists had intensified at the junction of Crumlin and Ardoyne roads. At Brompton Park, off the Crumlin Road, several vehicles were on fire and a line of six RUC Land Rovers were attacked with bottles and petrol bombs.
Local Sinn Fein assembly member Mr Gerry Kelly said nationalists were angry because the RUC had "forced" the parade through the area and hemmed people into their homes.
He also pointed out that the area was the scene of a recent tense stand-off between loyalists and parents of children attending a local Catholic school.
Local SDLP councillor Martin Morgan blamed the police for the violence. He claimed they had provoked the trouble.
Mr Kelly said he phoned Northern Secretary Mr John Reid and asked him to get the RUC to leave the area.
Sinn Fein said an 18-yearold man was hit in the chest by a plastic bullet. A man in his 30s suffered an eye injury and one baton round ricocheted off the head of a 16year-old girl.
Close to the city centre last night there was also trouble when two bands in the main Orange parade fell out and started fighting near Shaftesbury Square.
In the Short Strand area of east Belfast, police were deployed to separate rival loyalists and nationalists stoning each other.
Meanwhile, the RUC is investigating the shooting of a 22-year-old man found in a house at Mount Vernon Park in north Belfast last night. He was rushed to hospital where he underwent emergency surgery.
