Twenty six police officers have been injured during a night of riots in North Belfast.
Members of the PSNI came under attack from republicans and loyalists during violence linked to a nationalist parade through the area.
Bricks and stones were thrown at police lines as they separated the hostile factions. Three officers were taken to hospital. Police responded with water cannon.
Tensions have been simmering locally for days and there has been a war of words between political representatives over parading through the area.
A PSNI spokeswoman said: "Police are urging all individuals and communities affected to take a step back. Violence has serious and unwanted consequences for us all."
Police are continuing to deal with significant but localised disorder in the Carlisle Circus and Clifton Street area.
The summer marching season has polarised communities in North Belfast for many years, with regular violence at Ardoyne on the Twelfth of July which included gunshots this year. Despite this, most loyal order parades across Northern Ireland pass peacefully.
Efforts have been made by community representatives to reach a resolution for the remaining contentious ones. Unionists are bitterly opposed to the Parades Commission, which rules on where controversial marches can go and places conditions on them.
Northern Ireland First Minister Peter Robinson has said he is considering reopening efforts to deal with parading after a recent bid for a new deal collapsed following discussion with the Orange Order.
Although many parts of Northern Ireland have prospered, in working class North Belfast nationalist and unionist communities live separately, divided by interface barriers which have multiplied in number since the Good Friday Agreement of 1998 which enshrined political powersharing.