Fifteen police officers were injured during a second night of sectarian clashes in North Belfast, bringing the number of officers injured to 61.
Three were taken to hospital on Monday night during trouble that saw rioters hurl petrol bombs at police lines in the Carlisle Circus area of Belfast.
Officers used water cannons and fired six baton rounds at the crowds as troubled flared on Monday night.
Rioters also hurled stones, bottles, fireworks and rocks and hijacked a van in Denmark Street before pushing it towards police lines.
The extent of the injuries sustained by the police officers taken to hospital are not yet known.
Terry Spence, chairman of the Northern Ireland Police Federation, which represents rank and file officers, said: "Their bravery and courage in stark contrast to that of the cowardly thugs responsible for trying to murder them."
Assistant Chief Constable Will Kerr said: "I am very proud of how my colleagues stood in the face of danger, working to bring this situation under control, but I am saddened and angry that again we find ourselves subject to serious violence from the communities we serve.
"Let me be clear, we have made seven arrests already and with a robust criminal justice strategy in place, there will be more.
"The community of North Belfast needs to see a resolution to this issue now.
"Collectively, we cannot afford to wait and we cannot have night after night of violence on our streets. Following two nights of disorder, we have a number of police officers who are no longer available to deliver their core policing duties, protecting the communities they serve."
He said the violence had to be brought to an end.
"And the huge impact on Northern Ireland cannot be ignored. As we strive to promote our positive image, the negative effect of these violent pictures on jobs, tourism and investment cannot be underestimated. We do not want to take a backward step.
"I urge all those with influence to urgently use it to bring a resolution to the violence and work towards a longer-term solution for the issues affecting this area."
The Police Service of Northern Ireland advised motorists to avoid the Carlisle Circus area due to the disorder.
The latest disorder came after 47 PSNI officers were injured on Sunday night during riots linked to a republican parade nearby and a loyalist protest.