Loyalist gunmen opened fire on police and soldiers for a second night running amid ferocious new rioting on the streets of the North.
Blast, petrol and paint bombs were hurled at security lines across Belfast and parts of Co Antrim and Down.
At least seven more police officers were injured after 32 were wounded during the first night of violence linked to an Orange Order march rerouted away from Catholic homes.
They were pelted by a 700-strong mob on the Albertbridge Road in east Belfast, where a digger was hijacked and used to flatten street lights.
Police said a number of shots were fired at them on the nearby Newtownards Road, and at the Army on the Donegall Road, south Belfast.
New Barnsley police station in the west of the city was rocked by explosions. A car and van were crashed into its metal gates and attempts made to set a security hut ablaze with gas cylinders.
Cars and vans were hijacked and set on fire throughout Belfast, while in Bangor, Co Down a bus was burnt out by men who robbed passengers and ordered them out.
Plastic bullets and water canons were directed at rioters who set a bank and shops alight at Cloughfern, Newtownabbey, just outside north Belfast.
Attacks were also launched in Banbridge, Co Down, and Glengormley and Ballymena in Co Antrim.
Police arrested 10 people for rioting and two others charged earlier over the earlier disorder are due to appear at Belfast Magistrates Court today.
Chief Constable Hugh Orde will also brief Northern Ireland Secretary Peter Hain on the full scale of the violence which he described as some of the most dangerous faced by any police force in UK history.
As the trouble intensified a stretch of the Westlink motorway route through Belfast was shut.
Fresh trouble flared after police raided homes in their hunt for the terror thugs who unleashed shocking rioting in Belfast and surrounding towns on Saturday.
Chief Constable Orde has appointed one of his top detectives to lead a major investigation into the violence that followed the controversial Orange march in west Belfast on Saturday.
Loyalist paramilitary gunmen fired at least 50 shots at security lines during 12 hours of mayhem into Sunday morning.
Police and soldiers discharged 430 baton rounds and used water canons in a bid to drive back rioters. They also returned live fire.
Seven guns were seized and a bomb making factory was discovered in the Highfield estate, north Belfast.
One man was critically injured after being caught in an explosion while another member of the public was wounded in the gunfire.
More than 2,000 police officers and soldiers were needed to deal with the mayhem as it spread overnight into surrounding towns and villages in Co Antrim.
Cars, lorries and buses were being hijacked and set alight so regularly that roads were closed and motorists urged to stay at home.
As detectives began studying masses of CCTV footage in a bid to identify the Ulster Defence Association and Ulster Volunteer Force paramilitaries behind much of the chaos, Chief Constable Orde called his men and women heroes who could have been killed.
He said: “We are very lucky we do not have dead officers. They were shot at by paramilitary groups from the loyalist side.
“What I saw was a very professional response to one of the most dangerous riot situations in the history of policing in the United Kingdom. It is unique to Northern Ireland for officers to come under live fire in what was a public order situation.”
As well as making several arrests, police also have suspected gunmen captured on film.
After clashes in north, west and east Belfast, loyalists in the towns of Ballymena, Antrim, Carrickfergus, Larne, Ballyclare and Glengormley then either blocked roads or petrol bombed police.
Arsonists destroyed a branch of the Northern Bank in Cloughfern, Newtownabbey, although the safe survived intact.
Gangs of youths also gathered in the village of Ahoghill, Co Antrim, which has been blighted by several weeks of sectarian attacks, to burn out cars, attack homes and pelt police with fireworks.
The disorder forced the cancellation of Mass at Harryville Catholic church in Ballymena, which has been plagued by sectarian hatred in the past.
Mr Hain condemned those involved and challenged Orangemen and unionist politicians to be equally critical.
He said: “This rioting and attacks on the police and army are totally unacceptable. Attempted murder cannot in any way be justified. There can be no ambiguity or excuse for breaking the law.”