Bricks and bottles were thrown as police moved in to assist in the removal of a bonfire in north Belfast.
The bonfire in the New Lodge area was planned to be lit tonight to mark the anniversary of the introduction of internment in 1971.
Police have now pulled out of the area following a stand-off with republican youths
In a statement, a PSNI spokesman said: "Police are currently in attendance at Queens Parade in the New Lodge area of North Belfast to support contractors who have been tasked by the landowner to remove a bonfire from the road.
Scores of PSNI departed the New Lodge estate at speed amid a hail of missiles fired by the young people.
The estate was later barricaded using metal fencing while teenagers held their hands up in triumph from atop the anti-internment pyre.
Police had moved in earlier to facilitate contractors who have been tasked with removing the structure.
Earlier, a small number of bottles and pieces of wood had been thrown at officers.
The New Lodge is a mainly nationalist area dominated by decades-old public housing blocks.
The bonfire is made of wooden pallets and has an Irish tricolour flag on top.
Police vehicles have entirely blocked off the site of the bonfire on a grassy area beside the residential towers.
Officers are using a camera on top of one vehicle to gather evidence.
One officer was helped from a vehicle and driven away following the scuffles.
Footage posted to social media showed one officer collapsing as police with riot shields fended off demonstrators.
Locals claimed rioters had been seen throwing fireworks, bricks and bottles, with children, with one onlooker claiming children as young as ten were among the crowds clashing with police.
Mark Lindsay, chair of the Police Federation for Northern Ireland, condemned attacks on officers.
He said: "Officers trying to protect the community and lawful agencies are once again caught in the middle and in the firing line.
"They are being attacked with a range of missiles and iron fencing. In one assault by a mob, one officer is seen to be struck and knocked to the ground.
"This behaviour is contrary to the overwhelming wishes of the people of New Lodge, who do not want this bonfire or their area hijacked by young thugs."
He said officers are acting with professionalism and restraint, and urged those orchestrating these "vicious and unacceptable" confrontations to pull back before people are seriously injured.
"These are ugly scenes reminiscent of the past and do not need to be repeated as communities work to build a better future. They are disgraceful and unacceptable.
"I know local community and political figures are trying to intervene to get order restored and, from our perspective, we hope they are successful.
"In the meantime, our officers will continue to do the job they are there to do."