Riot police in the Netherlands have clashed with protesters angry at new coronavirus restrictions.
Officers used water cannon and tear gas to clear demonstrators in Eindhoven. They had gathered in defiance of a new 21:00 (20:00 GMT) curfew.
Some protesters threw fireworks, looted supermarkets and smashed shop windows. There were smaller demonstrations in the capital, Amsterdam.
More than 100 people have been arrested.
Some of the demonstrators threw fireworks and grabbed bicycles to build barricades against the police, who eventually used tear gas to clear the streets.
A Covid-19 testing centre was also set alight on Saturday evening in the northern village of Urk, local authorities said.
"The fire in a screening centre in Urk goes beyond all limits," Health Minister Hugo de Jonge said.
The 21:00 to 04:30 curfew, enforced on Saturday, is the first in the Netherlands since World War II. Violators face a €95 (£84) fine.
Restrictions were delayed - now the backlash
Burning bikes were built into barricades, supermarkets looted.
In Eindhoven, golf balls and fireworks were hurled at police in full riot gear, who eventually used tear gas to clear the crowds.
The scenes of violent unrest spread across the country: Amsterdam, Tilburg and Enschede, where young men threw stones at a hospital and torched a Covid testing centre.
National Security Council Chairman Hubert Bruls said that, while he understood the protesters' frustrations, the more the Dutch persevere now, the sooner they can get their freedoms back. He labelled those involved in the violence not demonstrators, but "corona hooligans".
Actually many see vaccines as the key, and the Netherlands is lagging behind there - last in the EU to roll out its vaccine programme, to date 77,000 people have been given their first dose.
At the start of the outbreak, the Dutch government resisted measures like masks and curfews, telling Dutch citizens they were sensible, rule-abiding and didn't need to be treated like children.
That sense of exceptionalism has come back to haunt them. Almost a year on, some people are struggling to do the mental pivot required to accept that the Netherlands has been forced to introduce draconian measures it initially dismissed.
The curfew was passed in parliament on Thursday, albeit with a slightly later start time than the proposed 20:30.
The country's bars and restaurants have been shut since October, while schools and non-essential shops closed last month.
A ban on flights from the UK, South Africa and South America has been put in place due to fears over new variants of the virus.
There have been more than 944,000 cases and 13,646 confirmed deaths from Covid-19 in the Netherlands.