LONDON (AP) — Violent clashes erupted in central Dublin on Thursday evening, with vehicles set on fire and riot police attacked, after a five-year-old girl was seriously injured in a knife attack earlier in the day that also left a woman and two People were killed and other small children were hospitalized.

Irish police said the girl was receiving emergency medical treatment in a Dublin hospital after the attack outside a school. Shortly after that announcement, at least 100 people took to the streets, some armed with metal bars and their faces covered.

Police said over 400 officers, including many in riot gear, were deployed in Dublin city center to contain the unrest, which they said was “caused by a small group of thugs”. A police cordon was also set up around the Irish Parliament building, Leinster House, and officers from the Mounted Support Unit were stationed on nearby Grafton Street.

Clashes broke out with riot police as some protesters fired flares and fireworks while others grabbed chairs and stools outside bars and restaurants.

During the riots, several police vehicles and a tram were damaged, and a bus and a car were set on fire on the city’s O’Connell Bridge.

Shop windows were regularly smashed and a Foot Locker store was looted. All public transport in the city – trams and buses – was suspended and many companies asked their employees to work from home on Friday.

“We have a completely insane hooligan faction driven by a far-right ideology and even then this disruptive tendency that carries out serious violence,” said Ireland’s top police officer Drew Harris.

Police and politicians called for calm and warned against misinformation about the attack earlier in the day.

“The scenes we are witnessing in our city center this evening cannot and will not be tolerated,” said Justice Minister Helen McEntee. “A brutal and manipulative element cannot be allowed to take advantage of a terrible tragedy to wreak havoc.”

Police had previously said a man in his 50s, who was also seriously injured, was a “person of interest” in their investigation. No further details about his identity were revealed.

At a news conference that evening, Harris was asked about a possible terrorist connection and he did not rule it out.

“I have never ruled out a possible motive for this attack… All investigations are open to determine the motive for this attack,” he said.

That appeared to be a slight change in attitude from earlier, when Superintendent Liam Geraghty said police were open to the investigation but were “satisfied there is no connection to terrorists”.

A 30-year-old woman also suffered serious injuries in the knife attack shortly after 1:30 p.m. The other two children, a 5-year-old boy and a 6-year-old girl, suffered less serious injuries. and the boy was released from a hospital,

Geraghty told a media briefing that there was preliminary evidence that a man attacked several people in Parnell Square East.

He said police believe it was “an independent incident, not necessarily related to larger issues in the country or the city, and we need to determine the exact reasons for this.”

Geraghty confirmed previous witness reports that a knife was used in the attack, but could not provide further details about the nature of the injuries. He also confirmed that witnesses tried to disarm the man as soon as they saw what was happening.

“It is my understanding that members of the public intervened at a very, very early stage and we would applaud those members of the public for engaging in such a traumatic and potentially dangerous situation,” Geraghty said.