Dublin, Nov 24 : Protesters clashed with police in Dublin and torched several vehicles after a knife attack in the city centre on Thursday left four people, including three children, injured. The Irish police chief blamed the unrest on a "lunatic, hooligan faction driven by far-right ideology" while President Michael D. Higgins said that the earlier attack is being "abused by groups with an agenda", the BBC reported. Public transport remained disrupted in parts of the Irish capital, and an ambulance service said that it's "extremely busy" tonight. More than 400 Irish police officers were involved in the height of the response. In a video statement on social media, Chief Superintendent Patrick McMenamin said some members of the police force had been attacked and assaulted, The Guardian reported. However, he said no serious injuries had been reported by gardai (Irish police force) or members of the public. Gardai remained on patrol in the city centre, he said, adding: "Dublin city centre is now calm and returning to normal". The violence broke out after three young children and a woman were attacked in Parnell Square East in the north of the city centre. Police detained a man in his 50s, who was also being treated for injuries, and said they were not seeking other suspects. /IANS