Sixteen police officers were injured during sectarian riots between republicans and loyalists in east Belfast today.
Water cannons and non-lethal baton rounds were fired by officers as they came under a hail of bricks and fireworks when they separated the opposing factions at an interface flashpoint on the Albertbridge Road near Short Strand.
Demonstrators were returning from a 1,000-strong protest outside Belfast City Hall against the council's decision to restrict the flying of the Union flag.
Countless roads have been blocked during the loyalist campaign - in one case north of Belfast a pensioner trying to visit his dying wife in hospital was turned back.
He said: "If your wife was dying what would you be doing? Have a bit of sense. Protestants, you don't know the meaning of the word, take yourselves home, show a bit of respect for people."
They responded by jeering "cheerio" in a recording made by the BBC.
In west Belfast a GP was twice prevented from attending a home visit with a patient terminally ill with cancer.
Nationalist SDLP MLA Conall McDevitt said: "These are depraved acts which immediately dismiss any claim on a protest being peaceful."
Senior politicians from Belfast, Dublin and London are to meet next week to discuss the protests after more than 40 days of road blocks and sporadic violence by loyalists failed to produce a solution.
Stormont First Minister Peter Robinson and his deputy Martin McGuinness will join Northern Ireland Secretary Theresa Villiers and Ireland's Tanaiste (deputy leader) Eamonn Gilmore.
Mr Gilmore said: "This violence is being orchestrated and those behind it are known criminals, intent on creating chaos.
"This has nothing to do with real issues around flags and identity in a shared society, which are the subject of intensive political discussions at present."
Ms Villiers urged restraint.
"We can't afford to have these continuing protests damage our economy and destroy potential jobs for Northern Ireland's young people," she said.
Demonstrations against Belfast City Council's decision to hoist the Union flag from the City Hall only on designated days like royal birthdays have brought many parts of Northern Ireland to a standstill.
Almost 100 officers have been injured and over 100 arrests made during weeks of sporadic trouble, the Police Service of Northern Ireland (PSNI) said.
Businesses in Belfast's city centre have struggled to cope, with many reporting lost trade, and the Confederation of British Industry (CBI) warned some investors may think again.
A second peace rally is to be held outside Belfast City Hall tomorrow.
Sinn Fein President Gerry Adams said there should be a cross-community response.
"But there can be no going back. The tiny minorities who want to cling to the past must be rejected. Sectarianism must be tackled and ended."
Ulster Unionist Party leader Mike Nesbitt has co-chaired a unionist forum designed to address grievances.
"Street violence from so-called unionists, no matter what age, advances nothing but the cause of Irish nationalism. It is high time those involved in rioting realised they are destroying the very cause the hope to promote."