Dozens are injured as militants demonstrate against hard-line Protestant parades.
Officers of the Royal Ulster Constabulary clashed Saturday in cities across Northern Ireland with Roman Catholic militants protesting Protestant parades through their neighborhoods.
At least five people were arrested and scores were injured, most of them not seriously, as protesters confronted police officers seeking to clear them from the parades.
The demonstrators shouted abuse at the marchers, who were celebrating the 310th anniversary of the defeat of James II, a Catholic, in Londonderry.
The demonstrations over the parades, which many Catholics find insulting, occurred in Belfast, Lurgan and Londonderry. They came as the people of Omagh, in the center of the predominantly Protestant British province, prepared to commemorate the first anniversary of a bombing by a splinter group of the Irish Republican Army that killed 29 people and injured 330.
Sinn Fein, the political wing of the IRA, accused the police of brutality, which the police denied. In the past, Sinn Fein President Gerry Adams has acknowledged that Catholic protests over the Protestant parades are part of a strategy to advance Sinn Fein's position in the northern peace effort.
The negotiations have been stalled for more than a year in a dispute over the disarmament of the IRA and over Cabinet posts for Sinn Fein in the Northern Ireland Assembly. The Assembly was created under the 1998 peace agreement to give the province's minority Catholics more power.
Many officials, including mainstream Catholic politicians, said Sinn Fein was using the protests to satisfy hard-line members of the IRA who are restless with Adams' policy of trying to negotiate with the Protestant unionist majority.
Saturday's demonstrations, the officials said, also had the effect of counterbalancing the plan for a memorial service today in Omagh for victims of last year's bombing by the splinter group, which called itself the Real IRA.
The main IRA has observed a cease-fire for two years but has refused to disarm.
In Belfast on Saturday morning, police said 19 officers and several civilians were injured in clashes on Lower Ormeau Road as about 20 members of the Protestant Apprentice Boys of Derry marched through the area. There were no arrests.
Television on Saturday night showed police officers dragging sitting protesters off Lower Ormeau Road. They responded by kicking. The police then clubbed the protesters' legs.
Gerald Rice, leader of the Catholic neighborhood group and a former IRA prisoner in a British jail, said the police had been "brutal, absolutely brutal," in clearing several hundred protesters out of the way of the march.
The marchers then boarded a bus for Londonderry, for ceremonies honoring the young apprentices who in 1689 locked the gates of the city against James II. James was eventually defeated by his Protestant son-in-law, William of Orange.
In Lurgan, 20 miles west of Belfast, police said protesters in a Catholic area threw gasoline bombs and rocks at police officers and that several masked men attacked police lines with cudgels. The police said they fired five plastic bullets and made five arrests.
In Londonderry, a Protestant parade in the city center passed without significant violence along the old wall of the city, near the Catholic Bogside area. Two cars, apparently owned by Protestants, were hijacked and burned.
More than 1,000 police officers were deployed in Londonderry, which Catholics call Derry.
Catholic men and youths hurled stones, bottles and 130 gasoline bombs at the lines of heavily protected riot police, who ensured there were no direct Protestant-Catholic clashes. At least eight officers suffered minor injuries.
Police, backed by British soldiers, were prepared for increased confrontations with Catholic protesters after dark.
The violence overshadowed efforts by more moderate Protestants and Catholics to commemorate the bombing anniversary.
Businesses in Omagh closed in the afternoon in remembrance of Saturday, Aug. 15, 1998, when police, responding to a misleading telephoned warning, unwittingly herded workers, shoppers and tourists toward the car bomb.
Only one man has been charged in connection with the attack.
_ Information from the Associated Press was used in this report.