Belfast, N. Ireland (CNN) - Police officers in Northern Ireland came under attack during a third consecutive night of disturbances in Belfast, police said late Tuesday.
A crowd of up to 200 people gathered in the pro-British Denmark Street area of the city. Youths, some hooded, pelted officers with fireworks, bricks, bottles and other objects, including golf balls, officials said.
Police warned drivers to avoid the district, close to the city center, and roads were closed for a time.
The violence on Tuesday appeared to be less intense than the two previous nights when more than 60 police officers were injured trying to keep the peace during disturbances. Six people were arrested Tuesday and three officers suffered injuries that did not require medical treatment, police said.
Police said the disorder was linked to tensions between Catholics and Protestants over parades in a district near Carlisle Circus.
Several youths charged with public order offenses late Monday were scheduled to appear in court Wednesday.
Assistant Chief Constable Will Kerr on Tuesday urged politicians and community leaders to "stop posturing" and "sort out" the violence before someone is killed.
He warned that a solution must be found before September 29, when Protestants plan one of their biggest parades in years.
Police officers Monday had been trying to maintain order as Protestant demonstrators voiced their opposition to a scheduled parade by a Catholic marching band and its supporters.
Hundreds of parades take place across Northern Ireland each year, the majority involving the Protestant Orange Order and associated organizations, although pro-Irish nationalists also have marches.
The Northern Ireland Parades Commission rules on which marches are allowed to take place and which are banned, in an effort to keep friction to a minimum.
Most parades pass off peacefully, but when members of one community march near or through neighborhoods dominated by another, violence sometimes results.
Sunday night's violence, which took place near Ardoyne, came as Protestants who want Northern Ireland to remain part of the United Kingdom clashed with Catholics who want the province to become part of the Republic of Ireland.