Garda reaction: An Garda Síochána had "no intelligence" that violence would erupt as a result of the planned Love Ulster march in Dublin on Saturday, Assistant Garda Commissioner Al McHugh said.
The actions taken by the gardaí before and during the parade were appropriate, he said.
Mr McHugh said he had met the march organisers Fair (Families Acting for Innocent Relatives), and Republican Sinn Féin had also indicated they were organising a counter-protest, but that the event was hijacked by people who were not in the main from any political group.
Two inspectors were appointed to liaise with Fair last January and it was agreed there would be no sectarian music played and no paramilitary regalia displayed, he said. Intelligence indicated that the counter-protest would be peaceful.
He said there was "no intelligence whatsoever to indicate that the violence or even the planned violence that took place yesterday in Dublin was going to take place".
Mr McHugh was speaking on RTÉ's This Week programme yesterday. When asked if he was aware of internet postings or articles in Sinn Féin's paper, Saoirse, encouraging protests, and if he knew the Taoiseach had heard rumours relating to the demonstration, he said: "The intelligence that was available to us from different sources, including the PSNI, was that no high-grade marching or protesting was going to take place on the day."
Before the march began, Republican Sinn Féin took a position at the top of O'Connell Street but, he said, a separate group of protesters then emerged.
"What effectively took place then was the parade was high-jacked by a number of hoodlums and gangsters who came out of a lot of the local pubs, who were hell-bent on causing damage, who were armed with hammers, petrol bombs."
Many involved were minors without political affiliation, he said. "Most of the people involved were non-party, weren't part of any particular political group and if you look at the age group, there were 42 people arrested, many of those were 16 and 17 years of age. They were technically children. Society has a lot of questions to answer if young people of that age could come in and behave in the manner in which they behaved."