 Riot police reacted to protests after five people were injured in a knife attack in Central Dublin on November 23.Police said they had not ruled out any motive over, including whether it could be terror-related, the incident sparked clashes between riot police and a group of anti-immigrant protesters, who arrived on the scene near the main thoroughfare of O'Connell Street shortly after the attack.A police car and double-decker bus were burned out and windows smashed in at a nearby Holiday Inn. Hotel in McDonald's restaurant.A five-year-old girl was receiving emergency treatment after sustaining serious injuries in the stabbing. A man in his late 40s, also being treated for serious injuries, was arrested by police who said they are not looking for any other suspect.Police said it appeared the man attacked a number of people on Dublin's Parnell Square shortly after 1330 GMT. Members of the public intervened at an early stage of the attack.