The Dutch government says it will not lift a curfew, after a third night of violent protests against increased Covid curbs across the Netherlands.
Shops in Rotterdam and other cities were looted and Finance Minister Wopke Hoekstra said: "It's scum doing this". More than 180 arrests have been made.
The Dutch chief of police said the riots no longer had "anything to do with the basic right to demonstrate".
The criminal violence had to stop, said Prime Minister Mark Rutte.
Shop-owners in Rotterdam, Den Bosch and other cities spent Tuesday morning cleaning up the debris from Monday night's violence.
Rotterdam Mayor Ahmed Aboutaleb sent a passionate message to "shameless thieves" who had caused the damage: "Does it make you feel good that you've helped ruin your city? To wake up with a bag full of stolen stuff beside you?"
A night-time curfew from 21:00 (20:00 GMT) to 04:30 was imposed last Saturday to halt the spread of the virus. Anyone caught violating it faces a €95 (£84) fine. Mr Hoekstra said they would not "capitulate to a few idiots" and anyone who caused damage should be tracked down and be made to pay for it.
The Netherlands has had nearly a million confirmed Covid cases since the start of the outbreak, with more than 13,500 deaths, according to Johns Hopkins University in the US, which is tracking the pandemic.
What happened on Monday night
Riot police clashed with protesters in Rotterdam and Amsterdam, as well as Amersfoort, Den Bosch, Alphen and Helmond.
Some of the worst disturbances were in the south of Rotterdam where police said 10 officers were hurt. Most of the rioters were youths or young men, and Amsterdam's mayor appealed to parents to keep young people indoors.
Fires were lit on the streets of The Hague, where police on bicycles attempted to move small clusters of men who threw stones and fireworks.
In Den Bosch in the south, rioters set off fireworks, broke windows, looted a supermarket and overturned cars. A local woman told Dutch radio that masked youths had left a trail of destruction in the city centre. "I saw windows smashed and fireworks going off. Really crazy, just like a war zone," she said.
Roads into Den Bosch were closed to stop people joining the rioters and Mayor Jack Mikkers imposed an emergency order banning gatherings on Tuesday.
The region's chief prosecutor, Heleen Rutgers, urged parents to ensure teenagers stayed at home. "Start talking about how to respond to calls on social media to go and turn up somewhere," she told public broadcaster NOS.
In some southern cities, such as Maastricht and Breda, football fans marched through the centres promising to protect them from rioters. Ex-football international Robin van Persie appealed to people in Rotterdam to keep "our beautiful city" intact.
What's behind the riots?
The ignition of discontent has rocked the core of Dutch society.
In the absence of any legitimate way to socialise, is this simply an outlet for young men to feel part of something, their masks concealing their identities and enabling them to violently channel their frustrations?
There are more sinister influences at play. Messages on social media, overt and covert, have whipped up anger. Misinformation has even been spread by some politicians.
Some feared a curfew would be a tipping point, as Dutch restrictions tighten while some neighbouring countries relax their rules. The vast majority of people in the Netherlands are peacefully observing the curfew.
The unrest was initially seen as a response to the first "stay-at-home" order imposed since Nazi occupation during World War Two. That notion has been dismissed by Prime Minister Mark Rutte, who said the rioters were simply criminals and would be treated as such.
But there are simmering anxieties in Dutch towns and cities, and with less than two months before a general election, voters are vulnerable and the streets volatile.
How Netherlands has reacted
There has been widespread shock at the violence. In Rotterdam, where police used water cannon against the rioters, the mayor signed an emergency decree, giving police broader powers of arrest.
The prime minister said the police had the government's full support: "The riots have nothing to do with protesting or fighting for freedom."
Rotterdam shop-owner Emrah Köker said he had no words for what he had seen. "How can this happen in the Netherlands?" he asked Dutch daily newspaper Algemeen Dagblad. The justice minister said he challenged anyone to explain what looting a shop had to do with coronavirus.
In Den Bosch, Maaike Neuféglise said the damage to her shop was heartbreaking and ran into thousands of euros. "Everything's ruined. I saw the videos, it was a complete invasion. There must have been 40 people in our store," she told broadcaster Omroep Brabant.
The city's mayor said police had struggled to respond to the violence because they were needed in other nearby towns.