Buses and police vehicles were torched and shops looted as anti-immigrant protesters took to the streets in Dublin after three young children were injured in a knife attack.
"They are disgraceful scenes. We have a complete lunatic, hooligan faction driven by far-right ideology engaged in serious violence," Police Commissioner Drew Harris told reporters after deploying 400 officers to restore public order.
He added that all lines of inquiry related to the attack remained open, contradicting a senior officer who had earlier told reporters that police were satisfied the incident was not terror-related.
"I'm not going to speculate any further in respect of a terrorist motive. Until we're sure what the motive is, we have to keep an open mind as to why this happened."
The unreset came after a five-year-old girl sustained serious injuries in the knife attack at the City Centre, with two more children and two adults taken to hospital with injuries.
Police said it appeared the man, whose nationality they did not reveal, attacked a number of people on Dublin's Parnell Square.
Israeli strikes pummelled south Beirut on Monday, Lebanese official media said, while health authorities reported 31 people killed across the country, most of them in the south.
At least one police officer was killed and dozens of people injured in Pakistan as supporters of jailed former Prime Minister Imran Khan clashed with security forces outside the capital Islamabad on Monday, officials and Khan's party said.
A small plane travelling to Costa Rica's capital of San Jose crashed on Monday afternoon, authorities said, killing five of the six passengers on board.
Sectarian fighting in northwestern Pakistan which killed more than 80 people last week restarted on Monday, officials said, breaching a seven-day brokered ceasefire.
A US judge on Monday dismissed the federal criminal case accusing Donald Trump of attempting to overturn his 2020 election defeat after prosecutors moved to drop the case and a second case against the president-elect, citing Justice Department policy against prosecuting a sitting president.