Shocked tourists were left stunned at the sheer scale of the heavy police presence in Belfast's main shopping area.
lex Prentice (26) and William Woodward (23) from Leeds, said they were unnerved by the sight of dozens of armoured police Land Rovers.
"There were 14 police vans at McDonald's and we could see police officers with guns," said Alex. "We were just curious as to what was going on. We asked someone and they said there was a march on internment."
William said: "We thought all the marches were over.
"It wouldn't really stop us coming back. It is sad to see here quite divided. We have had a lovely time so far."
Dana Roemling (27), from Dusseldorf in Germany, said the violence may not be good for Belfast's image but that she was "not really nervous".
"We have a couple of problems in Germany with parades and police coming down on the political right and left, leading to clashes," she said.
Clara Gomez from Spain and Matthias Brochez from Switzerland were shopping in town despite warnings of trouble.
"The hotel told us there could be some trouble here today, but it didn't stop us coming out," said Clara.
"For me, it is sad what is happening," added Matthias.
Mertxe Hurrioz from the Basque Country was not afraid. "We have just been to the Titanic Centre and we will be carrying on with our plans," she said.
Normal Sunday shoppers were also thin on the ground with some shops not opening or opening late and people staying away for fear of trouble.
Tourism Minister Jonathan Bell said: "We are trying to promote Northern Ireland as a welcoming and friendly place to stay. On the streets of Belfast today people were greeted by police Land Rovers and crowds of people who are apologists for terrorists.
"That is not the sort of Northern Ireland we want the world to see. Northern Ireland is known for its scenery and its tourism and we hope it will continue to be."
Glyn Roberts from the Northern Ireland Independent Retail Trade Association said blocking off part of Royal Avenue early on Sunday afternoon would have had an "obvious" impact on trade and hoped lessons could be learned for next year.
"We are pleased there was no widespread disruption or violence in the city centre, though there was obviously a tense situation in north Belfast," he said. "Every trading day is important."