BELFAST: At Belfast City Hall, the flagpole is bare - and the streets are filled with nighttime fear and fury.

These are dangerous times in Northern Ireland, a long-divided corner of the United Kingdom that is supposed to be at peace after decades of unrest thanks to its hard-won cease-fires and a Catholic-Protestant government. But the lowering of a single Union Jack has exposed a society still split between two competing identities.

Last month, Catholics who narrowly outnumber Protestants on the council voted to reduce the flying of the flag to just 18 official days a year, ending a century when the British national symbol favored by Protestants flew uninterrupted year-round.

Catholics billed the move as a compromise, since they wanted the flag removed completely. On Wednesday, the flag fluttered for the first time since the vote to mark the 31st birthday of Kate, Duchess of Cambridge, but was taken down again at sunset.

Protestant hard-liners have responded with nightly illegal street blockades that often have degenerated into street battles between riot police and masked protesters armed with everything from sledgehammers to snooker balls. Police say 66 officers have been wounded, including six this week, and more than 100 rioters arrested.

Nobody seems to know how, or when, the strife will end. While Northern Ireland suffers intercommunal conflict each summer because of traditional Protestant marches, this is the first time that Northern Ireland has suffered a month straight of angry civil disturbances in the winter.

Some analysts, reflecting on how past Northern Ireland crises have unfolded, suspect that the extremists won't stop until someone is killed.

"The quickest end looks like it would be in an atrocity. I fear that," said Duncan Morrow, a University of Ulster lecturer and former chief of Northern Ireland's Community Relations Council, a group that tries to bridge the persistent divide between Irish Catholics and British Protestants.

At the heart of the resumed conflict is the rapid change in Northern Ireland's population balance and political system.

Northern Ireland was created as a Protestant-majority state in the U.K. shortly before the overwhelmingly Catholic rest of Ireland won independence in 1922. But the days of Protestant domination of politics and the police are distant memories.

The latest census published last month shows Catholics in the majority in Belfast and gaining throughout Northern Ireland. The peace process has produced a new system in which a former Irish Republican Army commander now jointly leads the government, and a decade of preferential Catholic recruitment has produced a more Irish-oriented police force that Protestant militants increasingly view as the enemy.

For many Protestants, the change has overwhelmed the senses. Stripping "their" flag from City Hall has brought their central fear into focus - that they could become the minority in a land that eventually could fly the green, white and orange flag of the neighboring Republic of Ireland.

"The vote on the flag was a touchstone. It transformed Protestant and unionist frustration into outright anger," said Mike Nesbitt, leader of the No. 2 Protestant-backed party, the Ulster Unionists. "Even if you put the flag back up 365 days a year - and I accept it's not going to happen - that would not fix the anger on the streets."

Many shop and restaurant owners in downtown Belfast are fuming, too - about scared-off customers, bills they can't pay and a political culture that wreaks economic havoc over matters of symbolism. They blame Catholic politicians for picking a needless fight right before Christmas, and blame Protestants for inflaming mobs with no ability to rein them back in.

But Peter Robinson, the Protestant first minister of the government who still backs the protests so long as they remain peaceful, insists he's done all he can.

"I can't bring them off the streets," he said.