The stabbing occurred on Thursday afternoon in the city center. Police said a total of five people sustained injuries, including an adult male in his 50s who is "a person of interest in this investigation" and has been detained.
Protesters charged at the police cordon around the scene of the attack and set a patrol car on fire, the Irish Independent newspaper reported, adding that law enforcers had called for calm and warned against misinformation concerning the incident. The report also said that protesters set several cars, trams and buses on fire along O’Connell Street, on O'Connell Bridge and Parliament Street, as well as broke into and looted several stores.
"We have a complete lunatic hooligan faction driven by far-right ideology," Police Commissioner Drew Harris was quoted as saying by the newspaper.
He also urged the rioters to calm down, go home and let the investigation take its course.
The report also quoted Irish President Michael D. Higgins as saying that the attack on children was "horrific," and that the attack on the school is being "abused by groups with an agenda."
Irish broadcaster RTE reported that the country's law enforcement completely closed O'Connell Street to the public and cordoned off roads leading to O'Connell Street.
The broadcaster also reported that parts of Dublin's center were on fire and that all the city's bus services were suspended.
Chief Superintendent Patrick McMenamin said Thursday that the city center "is now calm and returning to normal," adding that more than 400 law enforcement officers "remain on patrol in Dublin City Centre."
"This violence had nothing to do with the violent assault which occurred on Parnell Square this afternoon. It was gratuitous thuggery. Public Transport was attacked, Garda vehicles were damaged and some commercial businesses were attacked. Thankfully, no serious injuries have been reported by the public as a result of tonight's violence," McMenamin said in a statement aired by Irish broadcasters, adding that some police officers "were attacked and assaulted, thankfully none were seriously injured and I commend them all on their bravery to protect our community."
The Irish Defense Forces on Thursday denied deploying its forces to the center of Dublin.
"Images circulating of Defence Forces vehicles in Dublin City Centre are not from this evening, but from a separate routine operation and have no connection to this evening's events," the army said on social media.
The defense forces also called on residents "to be sensitive to the spreading of disinformation."