Young rioters laughed as they attacked police lines in west Belfast.
Twenty-nine officers were injured – one with suspected broken vertebrae – at an anti-internment bonfire site in the Distillery Street area.
In a video circulating on social media a young man appears to direct rioters as he films the vicious attacks on Saturday.
Most of the rioters were unmasked as they hurled metal bars and lumps of concrete at retreating officers.
The video shows a line of riot squad officers slowly walking backwards towards Grosvenor Road with armoured Land Rovers at each side of the line. The man filming on his phone shouts “Get out of our estate, to f***” and then laughs.
The officers are impassive as the missiles hit their lines during the almost-four-minute clip. At one stage a young rioter is seen carrying a long baton which may have been dropped by an officer.
Three officers were hospitalised. Others suffered neck, back and head injuries, and concussion.
Mark Lindsay, Northern Ireland chair of the Police Federation, said: “Some have received quite serious injuries. We’re aware of one with potentially two broken vertebrae.
“Those could be career-ending injuries. They could be life-changing injuries.
“They are sick of being a punchbag for a society that has failed to tackle contentious issues.”
Bonfires are traditionally lit in some republican areas to mark the introduction of internment without trial in August 1971.
The scene in Distillery Street was in marked contrast to the New Lodge area of north Belfast, where teenagers agreed not to proceed with their bonfire and all wood was removed.
Several people were seriously injured last August in the New Lodge and dozens were arrested following a ten-hour stand-off between police and young people.
DUP leader and First Minister Arlene Foster said it was "important to see prosecutions in due course" while Justice Minister Naomi Long added it was "utterly intolerable that police officers have been targeted in this way".
She said a partnership approach between agencies had "allowed the vast majority of contentious bonfires to be removed or significantly reduced in scale without incident".
There was no comment from Sinn Fêin on the Distillery Street disorder, although the party has consistently called for anti-internment bonfires to cease.
Northern Ireland Policing Board chair Doug Garrett said: "Thankfully we have not seen this number of injuries for some time but that is little comfort to the officers who were subjected to this sustained violence and who have been left with a range of serious injuries as a result."
Policing Board member and Alliance MLA John Blair said "the people of the area have been quite clear they do not want these bonfires".
PSNI Superintendent Melanie Jones said "footage from evidence-gathering cameras will be reviewed and all efforts will be made to identify those involved".
"People who choose to engage in criminal and anti-social behaviour must understand it is unacceptable and must stop.
"Parents and guardians have an important obligation to keep young people safe by knowing where they are going and who they are with."
