BELFAST, Northern Ireland -- Protestant hardliners attacked lines of Belfast riot police Friday as Northern Ireland's annual mass marches by the Orange Order brotherhood reached a furious, chaotic end with running street battles at several conflict zones.
In north Belfast, police in flame-retardant suits and helmets deployed a half-dozen armored cars to block a road so that Protestant Orangemen could not march past the edge of Ardoyne, a militant Catholic district that has become the most bitterly contested spot on the city map.
Men jumped on top of the armored barricade and, as hundreds of marchers and supporters formed a sea of often alcohol-fueled fury behind them, wielded pipes, golf clubs, wood planks and even ceremonial swords to vandalize the police vans.
Emboldened, some threw bottles and bricks point-blank into police lines. Many in the mob cheered as one policeman, struck and knocked semiconscious, was dragged to safety by colleagues.
Officers responded by firing a massive mobile water cannon at the rioters, propelling at least one shirtless man sideways off the roof of an armored car and on to the pavement, his forehead split open.
But the Protestant crowd kept swelling and hurling objects into police lines, forcing officers to respond with volleys of snub-nosed plastic bullets in a failed bid to force the crowd to disperse or retreat.
During melees that lasted for hours, police said at least 23 officers and several rioters were injured, as was the Protestant politician who represents north Belfast in British Parliament, Nigel Dodds.
Dodds was struck in the head with a brick and knocked unconscious while talking to Orangemen standing near the police barricade. His Democratic Unionist Party, the largest in Northern Ireland, later said he had regained consciousness in Belfast's Royal Victoria Hospital.
Leaders of the Orange Order vowed to keep Protestants rallying to the confrontation zone until police caved in and permitted the march past Ardoyne.
The police commander, Chief Constable Matt Baggott, said his force would stand its ground and gather video evidence against the many hundreds of rioters.
Police were enforcing a surprise decision by a British-appointed Parades Commission to bar the Orangemen from using the main road beside Ardoyne to return Friday night to their nearby lodge, the first time such an order had been given.
The cross-community commission said it wanted Orangemen to stay away from that 300-yard stretch of road because, for the previous four years, Irish Republican Army splinter groups based in Ardoyne had attacked police with gunfire, grenades, firebombs and other weapons and wounded more than 250 officers in clashes that always followed the Orangemen's passage.
Orangemen accused the commission of surrendering to IRA violence and warned that both sides could play that game.
More than 4,000 Northern Irish officers and 630 reinforcements imported from Britain were deployed to keep control of the streets for this year's "Twelfth," Northern Ireland's official sectarian holiday, when the British Protestant majority commemorates a 17th-century military victory over their Irish Catholic foes.
In a sign that police expect Protestants to riot all weekend, police installed portable toilets and stacked pallets of bottled water for officers manning the armored-car barricades near Ardoyne. Commanders requested several hundred more police reinforcements from Britain due to arrive Saturday.
Police also faced angry crowds around Short Strand, the only Catholic enclave in otherwise Protestant east Belfast. There, rival crowds of youths traded salvos of bottles, bricks, golf balls, bolts and ball bearings over high security fences called "peace lines." Police suffered barrages of firebombs from the Protestant side and responded with more water-cannon blasts.
Police advised motorists to avoid much of north and east Belfast to avoid becoming trapped in the mob violence.
Before the rioting began, Orange leaders marched to the Parades Commission headquarters and unfurled a banner that read, "We will not be defeated. No surrender."
Orange leaders laid blame in advance for any bloodshed on the Parades Commission, which since 1997 has imposed restrictions on Orange marches to minimize conflict with Catholic communities.
Arguments over Friday's violence threatened to create a rift in Northern Ireland's unity government, a 6-year-old coalition of political extremes that has governed Northern Ireland with surprising stability in fulfillment of the territory's 1998 peace accord.
First Minister Peter Robinson, a Protestant who leads the Democratic Unionist Party, blamed Short Strand's Catholics for starting the rioting in east Belfast and the Parades Commission for creating an explosive situation in Ardoyne.
Robinson said Protestants felt "justifiable anger and frustration at the Parades Commission, who bear much responsibility for the situation in Belfast as do those who attacked parades as they passed certain locations." But he said Protestants' attacks on police and Catholics "can never be justified and must stop."
His major Catholic partners in government, the Irish nationalist Sinn Fein party, accused Robinson of blaming everyone but those most responsible: Orange Order leaders.
Deputy First Minister Martin McGuinness said Orange chiefs whipped Protestants into a frenzy and called their leadership "a disgrace."
His Sinn Fein colleague, Alex Maskey, called Robinson's response to the violence "disappointing and a failure in leadership."
Robinson is seeking an emergency recall of the Northern Ireland Assembly next week to debate the reasons for barring the Orangemen from Ardoyne and the causes of Friday's disorder.
"The Twelfth" commemorates the July 12, 1690, triumph of Protestant King William of Orange against the Catholic he dethroned, James II, in the Battle of the Boyne south of Belfast.
The Orange Order, founded in 1795 as a force for uniting often-feuding Protestant denominations under one anti-Catholic banner, was instrumental in creating Northern Ireland in 1921 shortly before the predominantly Catholic rest of Ireland won independence from Britain.
Catholic clashes with police over Protestant marches triggered the rise of Northern Ireland's modern conflict in 1969. The issue has defied resolution despite a two-decade peace process that has delivered paramilitary cease-fires, British military withdrawals, police reform and a power-sharing government.
Friday's approximately 550 Orange parades attracted unusually heavy crowds of spectators, who brought lawn chairs to the roadsides and basked in exceptional sunshine on what was the hottest, muggiest day of the year.
Among the Belfast spectators, many bedecked in Union Jack-patterned hats and sunglasses, was a sleeping infant bearing a bib that read, "My 1st Twelfth."