Anti-immigrant protesters have fought running battles with police, torched vehicles and looted shops in Dublin, after three young children were wounded in a knife attack outside a school, Irish officials said.
Police in riot gear stood guard on Thursday on the streets in the Irish capital as crowds taunted them with chants and set off fireworks.
Near O'Connell Bridge, over the River Liffey, flames rose from a torched car and bus, while crowds broke into stores and looted one of the city's main shopping streets.
The unrest — the worst in Dublin in years — came after a five-year-old girl sustained serious wounds in a suspected stabbing in Parnell Square East, north central Dublin.
Two other children and two adults — a woman and the suspected perpetrator of the attack — were taken to hospital after the incident around 1:30 pm [1330 GMT].
Rumours on social media about the nationality of the assailant, who police only described as a man in his fifties, helped fuel unrest following the attack.
Police chief Drew Harris blamed a "complete lunatic faction driven by far-right ideology" and warned against "misinformation".
Some protesters carried signs reading "Irish Lives Matter" and waved Irish flags through a neighbourhood home to a large immigrant community.
One protester told the AFP news agency that "Irish people are being attacked by these scum."
Ireland has been facing a chronic housing crisis, with the government estimating that there is a deficit of hundreds of thousands of homes for the general population.
Widespread dissatisfaction has fed into a backlash against asylum seekers and refugees, and far-right figures have promoted anti-immigration sentiment at rallies and on social media with claims that "Ireland is full".
By late evening, police chief superintendent Patrick McMenamin said calm had been restored, and no serious injuries were reported.
"It was gratuitous thuggery," he said.