The protests were initially against a curfew but have become violent, inspired by incitement on social media.
At least 70 people have been arrested after a third night of protests in the Netherlands.
The demonstrations were initially about opposing a curfew imposed by the government to tackle the coronavirus crisis.
But in some cities they sank into rioting and violence, with people’s motivation becoming less clear.
There have been clashes in cities including Amsterdam and Rotterdam, with police using tear gas and water cannon in an effort to disperse rioters.
People threw fireworks, looted shops and turned a car over onto its side, according to national broadcaster NOS.
In the city of Eindhoven, they torched a car, threw rocks and fireworks at officers, smashed windows and looted a supermarket.
Hundreds of rioters had already been arrested during the weekend, including some on suspicion of using social media to call for rioting, after a temporary COVID-19 testing station was burned down.
“It is unacceptable,” Prime Minister Mark Rutte said after Sunday night’s riots. “This has nothing to do with protesting, this is criminal violence and that’s how we’ll treat it.”
More protests are expected, with police union board member Koen Simmers telling TV programme Nieuwsuur: “We haven’t seen so much violence in 40 years”.
The curfew – in force between 9pm and 4.30am – is the first in the country since World War Two and was brought in amid fears of the COVID-19 variant discovered in the UK.
More than 5,700 fines have been issued to people for breaking the curfew, police said.
But he number of new cases has been declining in the Netherlands. The 4,129 new cases reported on Monday was the lowest daily increase since 1 December.
There have been 13,579 deaths in the Netherlands from COVID-19 and 952,950 infections.