BELFAST, Northern Ireland – Militant Catholics attacked riot police with homemade grenades and gasoline bombs Tuesday in an explosion of fury over the Orange Order, a Protestant brotherhood that staged mass parades across Northern Ireland.

About 60 officers and at least a dozen civilians, including several rioters, were wounded when Catholics from Ardoyne, an Irish Republican Army power base in north Belfast, hurled at least two of the grenades into columns of riot police.

Officers responded with water cannons, clubs and volleys of British-style plastic bullets that hadn’t been used in Northern Ireland since 2002. The hourlong riot was the worst violence on a day of dangerous street confrontations across this British territory.

The officers had forced Catholic protesters off a main Belfast thoroughfare to clear the way for a few hundred Orangemen, an anti-Catholic organization whose members parade each July 12.