Protestants determined to march through a Roman Catholic enclave rained stones, bottles and firecrackers on riot police Monday in the second day of a round-the-clock standoff.

Police fired plastic bullets at demonstrators who tried to cut through barbed-wire barriers and again when someone threw a firebomb at a police armored car.Leaders of the Orange Order, Northern Ireland's most influential Protestant group, vowed to hold their ground for days if necessary to win the battle of wills at a Drumcree church near Portadown, 25 miles southwest of Belfast.

The group is threatening civil disobedience unless several hundred Orangemen are allowed to march the Portadown route under police protection, as usually happens each year.

Several thousand Orangemen and supporters were at Drumcree. Smaller groups of Orangemen blocked roads in Belfast and towns throughout the British-ruled province late Sunday and early Monday in a bid to stretch police resources to the breaking point.

At least two policemen and two protesters suffered head wounds Sunday night around the Protestant church at Drumcree.

Early Monday, police fired plastic bullets at Protestant youths trying to breach barbed-wire defenses stretched for miles in pastures flanking the church. Elsewhere, Protestant mobs traded salvos with police and set cars on fire in Londonderry, the province's second-largest town, and Carrickfergus north of Belfast.

Meanwhile, police found the body of a Catholic man shot in the head in his taxi in a predominantly Catholic village near Port-a-down. It wasn't known if the death was related to the disturbances.

Protestant gangs set fire to cars and trucks around Portadown. In one incident, a crowd torched two vans seized from a business owned by Catholics.

At Drumcree, militants with tough faces, paramilitary tattoos and beer breath stood alongside middle-aged Orangemen, soberly dressed in dark suits with orange sashes.

On one side, the standoff involves 2,000 police standing and sleeping in shifts beside their clubs and shields, a backup battalion of British soldiers and an army helicopter overhead. They are determined to prevent the Orangeman from marching through hostile Catholic neighborhoods along the nearby Garvaghy Road.