Police in Northern Ireland have blamed the paramilitary Ulster Volunteer Force for an escalation in loyalist street violence following a Christmas lull.
Three nights of localised but sustained rioting have taken place in inner east Belfast, with reports of a gunman firing shots at officers and the use of dozens of petrol bombs as well as bricks and bottles.
Unionist politicians are due to meet this week in the hope of shaping a response that might bring the disruption to a halt, but all pleas to end the unrest have so far fallen on deaf ears.
A man in his 30s was being questioned by police on suspicion of attempted murder in connection with the gunfire, while more than a dozen others appeared at special court sittings, charged with offences including riotous behaviour. Some have been taken into custody.
Police said that individuals involved with the riots on Sunday, which broke out after up to 1000 loyalists demonstrated at Belfast City Hall, also aimed laser beams at officers and a police helicopter.
The riots have been accompanied by a new wave of non-violent but disruptive demonstrations in and around the city in protest against limitations on the display of the union flag at Belfast City Hall.
Churchmen and community leaders are involved in talks with loyalists in an attempt to defuse a dispute that has lasted more than a month and resulted in injuries to more than 60 police officers.
Northern Ireland's First Minister, Peter Robinson, said those involved were playing into the hands of republican dissidents. "The violence and destruction visited on the police is a disgrace, criminally wrong and cannot be justified."
The disruption has caused major damage to community relations, economic activity and the image of a region that has been seeking to attract investment and tourism, and the suggestion of UVF involvement will cause further alarm.
The Police Federation chairman Terry Spence described the appearance of gunfire as a very sinister development that had been orchestrated by the UVF.
"Paramilitaries have hijacked this flags protest issue and they have turned now their guns on the police. They are exploiting this."
Blaming police for clashes, prominent activist Jamie Bryson said on his Facebook page: "The fact that a large number of these officers are now Roman Catholics provides some explanation as to their bloodlust."
But Spence said: "I totally reject his comments. They are clearly sectarian and beneath contempt. Our officers are holding the line between anarchy and peace on our streets."
Glyn Roberts, of Northern Ireland's independent traders' association, said: "I would appeal to the people organising these riots to stop and consider the damage they are doing, not just to their own local community and their own local traders but to the reputation of Northern Ireland throughout the world."