By Toby Sterling
AMSTERDAM (Reuters) - Dutch Prime Minister Mark Rutte on Monday condemned riots across the country this weekend in which demonstrators attacked police and set fires to protest against a night-time curfew to slow the spread of the coronavirus, calling them "criminal violence".
The police said hundreds of people had been detained after incidents that began on Saturday evening and lasted until the early hours of Monday, including some in which rioters threw rocks and in one case knives at police and burned down a COVID-19 testing station.
"This has nothing to do with protest, this is criminal violence and we will treat it as such," Rutte told reporters outside his office in The Hague.
Schools and non-essential shops in the Netherlands have been shut since mid-December, following the closure of bars and restaurants two months earlier.
Rutte's government added the curfew as an additional lockdown measure from Saturday over fears that the British variant of COVID-19 may soon lead to an increase in cases.
There have been 13,540 deaths in the Netherlands from COVID-19 and 944,000 infections.
The police trade union NPB said there could be more protests ahead, as people grow increasingly frustrated with the country's months-long lockdown.
"We haven't seen so much violence in 40 years," union board member Koen Simmers said on television program Nieuwsuur.
Police used water cannon, dogs and officers on horseback to disperse a protest in central Amsterdam on Sunday afternoon. Nearly 200 people, some of them throwing stones and fireworks, were detained in the city.
In the southern city of Eindhoven, looters plundered stores at the train station and set cars and bikes on fire.
When police said the demonstrators were violating the country's current lockdown rules "they took weapons out of their pockets and immediately attacked the police", Eindhoven Mayor John Jorritsma said.
(Reporting by Toby Sterling; Editing by Catherine Evans and Alison Williams)