LONDON — Police in Northern Ireland fired plastic bullets and water cannon on rioters late on Monday in a second night of sectarian clashes between Catholics and Protestants that left nine police officers injured.

Police fired plastic rounds for the first time during the disturbances after protesters threw petrol bombs, fireworks, bricks, and stones at officers trying to separate rival groups in north Belfast.

Rioters from the Protestant group hijacked a van at one point and pushed it at police lines. At least three of the injured officers were taken to a hospital.

The second night of disturbances followed a march by a Catholic Irish nationalist band in an area where Protestant groups were recently barred from marching.

At least 47 officers were hurt in clashes on Sunday in the dispute over the rights of the two communities to hold parades in the area.

Last weekend, seven police officers were hurt in the same area when a Protestant band marched past a Catholic church playing music in defiance of a ban from the parades commission, which regulates marches in the province.

Paramilitary violence between the province's mainly Catholic republicans and pro-British Protestants — which raged on and off for three decades — has largely ended since a peace agreement was signed in 1998, but much of Belfast remains divided along sectarian lines.

Riots often erupt during the summer months when Protestant groups hold traditional parades that are seen as provocative by Catholic nationalists, many of whom want to be part of a united Ireland.