Northern Ireland riots 'will cost the police millions'
The Chief Constable in Northern Ireland has said the cost of policing Monday's violence will run into millions of pounds.
Rioters attacked police in several nationalist areas after parades by the loyalist Orange Order.
A policewoman suffered head injuries when a lump of concrete was dropped on her from a roof in north Belfast.
Another senior officer said political leaders must do more to prevent violence over the 12th of July period.
Assistant Chief Constable Alastair Finlay described the violence following the parades as "totally unacceptable".
He called on First Minister Peter Robinson and Deputy First Minister Martin McGuinness to show leadership.
"There are individual politicians working very hard on this but are we seeing the joined up government?
"Are we seeing this after a very difficult, damaging night for Northern Ireland?
"Are we seeing the first minister or the deputy first minister stepping out to condemn this and showing that they will have a plan to meet this type of issue next time it comes round rather than waiting until it inevitably comes next year.
"It's the police who will form that human barrier attempting to keep the peace."
The Chief Constable, Matt Baggott, said there would be an extensive follow-up investigation.
He was speaking as he released aerial footage of the violence at Ardoyne in North Belfast.
It showed officers coming under sustained attack from people throwing bricks and wielding metal bars and planks.
More than 100 riot police were involved in an operation to remove nationalist protesters blocking the Crumlin road, close to the Ardoyne, ahead of the return of an Orange Order march.
The crowd threw petrol bombs, a blast bomb and other missiles at police. The policewoman was struck on the head by debris thrown from the roof of the shops at about 2200 BST on Monday.
Police said they had to protect their injured colleague and ambulance crews from further missiles in Ardoyne as they tended to her, before she was taken to hospital.
Her condition is described as stable but "not serious".
The parade eventually went past the flashpoint area at Ardoyne shops. As it passed, stones and bottles were thrown.
The march had been delayed for about 90 minutes because of the protests.
The rioting in north Belfast continued for several hours. At one point, rioters used a laser pen to try to blind police officers.
Two people injured by police baton rounds were treated at the Royal Victoria Hospital in Belfast. They were later discharged.
There was sporadic violence in other parts of Belfast, Londonderry and Lurgan on the day Protestant Orangemen staged their main annual parades.
The Twelfth of July is the annual high-point of the loyal orders' parading calendar.
Some marches have been a source of tension between nationalists who see the parades as triumphalist and intimidating, and Orangemen who believe it is their right to walk on public roads.
In Londonderry, youths in the Bogside set a police car alight with petrol bombs and a gunman fired five shots at it. No-one was injured.
On the Ormeau Road bridge in south Belfast, petrol bombs and paint were thrown at police on Monday evening.
A car was later set alight on the bridge.
Police also dealt with minor disturbances on the Albertbridge Road and Short Strand area in the east of the city.
Police in riot gear responded to what a PSNI spokesperson described as "a major disturbance" at Botanic train station in south Belfast.
Dozens of police officers moved into the area after a disturbance on the platform.
A PSNI spokesman said two men and a woman would be reported to the Public Prosecution Service for alleged disorderly behaviour and assault on the police.
In west Belfast on Monday afternoon, a bus driver was forced to drive to a police station by two masked men who claimed they had left a bomb on the upper deck.
The men boarded the bus at Glencolin Walk shortly before 1600 BST.
He drove the bus to Woodbourne police station. Police later said the alert was a hoax.
In Lurgan, County Armagh, youths halted a train in the Lake Street area at about 1630 BST and attempted to set it on fire, but the driver managed to restart the vehicle.
None of the 55 passengers on board the Belfast to Dublin are believed to have been injured.
A van was also hijacked in the area.
Later, police said there was sporadic violence in the town's Antrim Road area, with petrol bombs being thrown at officers.
In Armagh city, a vehicle was set on fire on the Killylea Road and a large number of youths gathered.