Hundreds more police officers are to be drafted in to Northern Ireland from forces across the UK after three nights of rioting linked to a parades dispute.
Police Service of Northern Ireland Assistant Chief Constable Will Kerr said the mutual aid officers from England, Scotland and Wales will be used to bolster numbers at flashpoint areas in north and east Belfast which have seen the worst of the violence.
Mr Kerr, the officer in charge of the policing operation, said: "We will probably bring more mutual aid officers to continue through the week and to continue for as long as it is necessary.
"The Chief Constable has made it very, very clear we will have as many resources on the streets of Belfast for as long as it takes to protect communities and our officers across Northern Ireland."
A total of 44 police officers were injured and more than 49 people aged between 15 and 52 arrested during the disturbances which flared after Protestant Orangemen were prevented from walking along a 300m stretch of road which passes a nationalist area of north Belfast on Friday night.
A number of the officers were taken to hospital with suspected broken bones, and head and neck injuries after being attacked with ceremonial swords, bricks, bottles and huge pieces of masonry. Others were treated for heat exhaustion.
A special sitting of Belfast Magistrates' Court was held yesterday and to date 22 people have appeared before judges charged with public order offences.
Mr Kerr warned that the courts would be open "every day if necessary" to deal with the troublemakers.
More than 50 petrol bombs have been thrown at police lines, with a further 30 recovered by officers over the past three nights. Police have fired 49 plastic bullets in an attempt to quell the trouble.
Mr Kerr said the policing bill had already run into multiple millions of pounds.
He added: "It (the violence) was visceral. If you watch the footage of some of those people involved in attacking police lines on Friday night, particularly on Woodvale Road, their behaviour was almost animalistic.
"It was incredibly dangerous to engage in that sort of behaviour so quickly at police lines. The police officers who held the line at Woodvale Road and who continue to hold the line have shown incredible professionalism."
There have been repeated calls for calm including from Northern Ireland First Minister Peter Robinson, who visited the Woodvale area, which has seen the worst of the violence.
The Stormont Assembly has been re-called tomorrow to debate the fall-out from the determination by the Parades Commission banning the contentious march.
Meanwhile, the Orange Order, which has been widely criticised for calling people on to the streets without a plan, said the PSNI had questions to answer about how officers handled the situation.
A statement said: "The PSNI have serious questions to answer, not least, with so many police officers available, why were they unable to stop clearly orchestrated attacks, and, in the case of the Short Strand, a prolonged attack lasting over 30 minutes along the length of the peace wall?
"The violence, which we condemn, cannot be used as an excuse for not addressing the issues that have been raised by this ludicrous determination.
"There will be the blame game and point-scoring by all for the events that unfolded; however, the Orange institution will be scapegoated for where the responsibility for this crisis truly lies - at the door of the Parades Commission."
A DUP delegation including North Belfast MLAs Nelson McCausland and William Humphrey, East Belfast MLA Robin Newton and former Lord Mayor of Belfast Gavin Robinson were meeting senior police officers this morning to discuss the recent violence.