DUBLIN – Dublin witnessed a night of torched vehicles and store looting after a knife attack outside a school saw an “extraordinary” level of violence not seen in decades, police said on Friday.

The violence began when a group broke through a police cordon on Thursday in the area where three young children and a woman caring for them were injured in a knife attack.

Groups then set fire to buses and trams and looted shops on one of Dublin’s most famous thoroughfares, O’Connell Street.

Garda Commissioner Drew Harris told a news conference in the Irish capital on Friday that several Irish police officers were injured in an ongoing battle with the group that stormed the crime scene in Dublin on Thursday evening.

He said one officer was seriously injured and “numerous other members were injured” when rockets were thrown at them.

“What we saw last night was an extraordinary outbreak of violence,” Harris said. “These are scenes we haven’t seen in decades.”

Harris said “all lines of inquiry” are open to determine the motive for the knife attack.

Harris said 34 people were arrested following the “huge destruction” caused by the “riotous mob”, with 13 stores significantly damaged or looted.

A police cordon was set up around the Irish parliament building, Leinster House, late on Thursday evening amid fears that violence could spread.

“MOTIVATED BY HATE”

Irish Prime Minister Leo Varadkar said the protesters who fought police and looted shops were motivated by “hatred” and were “shaming Ireland”.

“Those involved have brought shame on Dublin, shame on Ireland and shame on their families and themselves,” Varadkar told reporters.

Harris, for his part, blamed the disruption on a “completely insane faction driven by right-wing extremist ideology.”

“We have a completely crazy hooligan faction that is driven by right-wing extremist ideologies, and even then this disruptive tendency that carries out serious violence.”

Harris said calm returned to the city shortly after midnight.

Irish Justice Minister Helen McEntee said the scenes of unrest were “unbearable” and that “an aggressive and manipulative element should not be allowed to exploit an appalling tragedy to cause chaos”.

“We will not tolerate a small number using a horrific incident to spread division,” she said.

Some protesters carried signs reading “Irish Lives Matter” and waved Irish flags through a home in the neighborhood of a large immigrant community.

One protester told AFP that “the Irish people are being attacked by these scum”.

Ireland is facing a chronic housing crisis and the government estimates there is a deficit of hundreds of thousands of homes for the general population.

Widespread discontent has led to a backlash against asylum seekers and refugees, and far-right figures have spread anti-immigrant sentiment at rallies and on social media, claiming that “Ireland is full.”