Up to 700 people are reported to be involved in fresh rioting in Belfast.
Cars have been hijacked and set alight and there are unconfirmed reports of bomb blasts in the city.
A bus full of passengers was also hijacked on the Belfast road in Bangor in Co Down.
The bus was driven from the Belfast Road to the Clandeboye Road where two men ordered all passengers off after stealing personal belongings from them. The bus was driven to the Green Road, Conlig and set alight.
Police said officers in the area came under attack from a crowd throwing petrol bombs and other missiles.
A 48-year-old man and a 16-year-old youth are due to appear before Laganside Magistrates Court in the morning in connection with Saturday's riots in Belfast.
The Chief Constable of Northern Ireland, Sir Hugh Orde, has said he is lucky not to have officers dead as a result of the violence.
He said the disturbances amounted to one of the most serious riot situations ever faced by a police force in these islands.
Over 2,000 police officers and British troops had to be deployed in an attempt to quell the rioting.
Several police officers and civilians were injured when hundreds of loyalists began rioting after a controversial re-routing of an Orange Order march in the west of the city.
The violence spread to several parts of Belfast and police came under sustained attack from blast and pipe bombs, bricks and automatic weapons. Police fired baton rounds in retaliation.
One PSNI vehicle was struck over 30 times by bullets fired by loyalist paramilitaries.
Masked youths hijacked cars and buses and set them on fire.
A disused garage also went up in flames and British Army explosives experts were brought in to defuse pipe bombs that had been seized.
Overnight disturbances also took place in Ballymena, Ballyclare, Monkstown, Aghoghill, Larne and Newtownabbey.
Some arrests were made, while in other cases police opted to use video evidence to initiate prosecutions at a later date. Hugh Orde described his officers as heroes in the way they dealt with the rioting.
The Taoiseach, Bertie Ahern, condemned yesterday's violence in Northern Ireland. He said that whatever grievances people might have, there was absolutely no justification for violence.
Mr Ahern said this was a time for strong leadership on all sides to help build a better, shared future and not revisit the failures and suffering of the past.
Orde slams Orange Order
The PSNI Chief Constable, Hugh Orde, said the Orange Order must bear substantial responsibility for the rioting as it had called on people to come out on to the streets.
He said such action meant the organisation could not shrug off responsibility for the violence.
The Orange Order said it noted the Chief Constable's 'intemperate, inflammatory and inaccurate remarks' and accused the police of being heavy handed and engaged in policing at its worst.
Mr Orde produced police film footage at his press conference showing Orange Order members confronting police with ceremonial swords.
