Dutch police used water cannons and tear gas to break up crowds as they arrested more than 180 people during a third night of violent protests against the government's coronavirus restrictions. Groups of youths threw fireworks, petrol bombs, looted shops and set fires in towns and cities across the country on Monday after the government imposed tough new measures at the weekend amid a sharp rise in new Covid-19 infections. At least 10 police officers were injured in the latest clashes. “All normal people will regard this with horror,” said Prime Minister Mark Rutte. “It is unacceptable. This has nothing to do with protesting, this is criminal violence and that's how we'll treat it.” Frustrations boiled over after protests against the country’s lockdown degenerated into vandalism, whipped up by messages on social media. The Netherlands imposed a tough five-week lockdown in mid-December, closing schools and non-essential businesses. Mr Rutte extended it for three weeks on January 12 over concerns about new Covid-19 variants. Last week, the Dutch government introduced a 9pm-4.30am curfew, and limited the number of guests people can have in their homes to one a day. The curfew is the nation’s first since the Second World War and followed a warning by authorities about a new wave of fast-spreading infections from a variant first seen in large numbers in southern England. The Netherlands has recorded more than 13,600 coronavirus-related deaths. Violence broke out on Saturday night when youths in the fishing village of Urk torched a Covid-19 testing centre. Monday night’s rioting was centred around the port city of Rotterdam, where police used water cannons to disperse rioters who looted shops. Once order had been restored the city's police announced on Twitter that “calm is slowly returning, but the atmosphere is still grim”. Trouble was reported in Amsterdam where protesters set fires in the street in defiance of the curfew. Police used tear gas on protesters in the western city of Haarlem as well. A number of towns and cities passed emergency decrees to give police extra powers to keep people away from key locations where violence was forecast. Calls were seen on social media for further violent protests, even as the country struggles to contain new coronavirus infections, bring down the death toll and ease pressure on its hospitals. Police in the southern town of Goes and the North Holland province said they detained people on suspicion of using social media to incite rioting. The worst violence on Sunday was in the southern city of Eindhoven, where police clashed with hundreds of rioters who torched a car, threw rocks and fireworks at officers, smashed windows and looted a supermarket at a railway station. “My city is crying, and so am I,” said Eindhoven mayor John Jorritsma. He called the rioters “the scum of the earth”. “I am afraid that if we continue down this path, we’re on our way to civil war," he said. He attributed some of the violence to football hooligans. Dr Tim Groot Kormelink, of the University of Amsterdam, said many of those protesting were just looking for "a thrill". "I wouldn't underestimate the number of young people that are 'just' followers and are looking for sensation, a thrill, an outlet," he told <em>The National</em>. Dr Judith Möller, assistant professor of Social and Behavioural Science at the University of Amsterdam, told <em>The National </em>the riots were the result of frustration over the pandemic. There has been growing discontent over the slow distribution of the vaccine across Europe. "The riots are connected to the curfew introduced on Saturday," Dr Moller said. "However, several people active in the anti-Corona measures movement have distanced themselves from the riots. "The riots really are a very unfortunate expression of the general frustration caused by the reality of living during a pandemic: both the consequences of the pandemic itself and the measures that affect the age group that is rioting possibly the most. "We already saw a surge in riots around New Year's Eve when fireworks were forbidden." Dr Joelle Swart, from the Centre for Media and Journalism Studies at the University of Groningen, said the protests have been hijacked by those wishing to cause discontent. "I believe there are three distinct subgroups that are involved and they are becoming mixed up here," she told The National. "First; peaceful protesters who are genuinely worried about the effects of the anti-corona measures, but did not necessarily intend to become part of riots; second, citizens who are frustrated by the limitations of everyday life during the pandemic and express their anger through violent behaviour to protest against the current governmental restrictions such as the curfew; and finally rioters who just attend for the purpose of rioting, piggybacking on the anti-corona protests. "As demonstrated by yesterday's riots, the latter two groups seem to be increasing at the moment." Chairman of the Dutch Security Council Hubert Bruls said the violence is not the mark of citizens concerned about their civil liberties. “These demonstrations are being hijacked by people who only want one thing and that is to riot,” said Mr Bruls,who is also mayor of the city of Nijmegen. "Of course there are also people who want to protest against the curfew and who want to speak up for their opinion. But the latter group was not on the street yesterday." Chief of Police Henk van Essen condemned the violence. “These riots no longer have anything to do with the fundamental right to demonstrate,” he said. “Respect for all colleagues who have had it hard for three nights.” Police unions said it was the worst rioting in four decades. On Tuesday, Dutch finance minister Wopke Hoekstra said those responsible for the riots were not legitimate protesters, adding: "Scum does this". "You don't capitulate to people who smash shop windows. That is not the case," he said.