Austria entered a national lockdown on Monday to contain a rapidly spreading coronavirus outbreak, becoming the first country in Western Europe to re-impose blanket restrictions since vaccines became widely available.
The country’s nine million people, including the fully vaccinated, will be banned from leaving their homes for 20 days except for essential purposes.
It is the strictest measure taken so far to stem a rising tide of Covid-19 infections across Europe, which German Health Minister Jens Spahn said on Monday would leave almost everyone in the country "vaccinated, cured or dead" by the end of winter.
Austria's measures led to weekend protests that the government said were infiltrated by neo-Nazis and other extremists.
Some protesters wore a yellow star reading “not vaccinated” in a provocative echo of the Star of David which Jews were forced to wear by the Nazis.
Interior Minister Karl Nehammer said that although many protesters were peaceful, the mood among unvaccinated people and opponents of restrictions was becoming more radicalised.
“There are worried citizens who want to express their discontent. But there is also a group who tries to hijack these demonstrations and use it for their own purposes, and that is the extreme right,” he said.
“There were well-known neo-Nazis from days gone by, as well as representatives of the new extreme-right scene.”
Mr Nehammer said hooligans had clashed with police, and revealed that death threats had been made against Austria’s chancellor and health minister because of the restrictions.
About 66 per cent of Austria’s population is fully vaccinated, one of the lower rates in Western Europe. Compulsory shots will take effect from February.
David Nabarro, a special envoy for the World Health Organisation, said the UN agency was worried by polarised views on the virus.
“There’s only one way to deal with this, and that’s partnerships between governments and people,” he told BBC Radio 4’s Today programme.
“Of course, if that’s going to be turned into polarisation, that gets to be extremely challenging.”
Asked about compulsory vaccinations, he said he wished they were not necessary but could become so if health systems came under strain.
The Austrian protests came amid sometimes violent rallies across Europe as the restrictions gradually lifted over the past year start to come back into play.
About 35,000 protested in Brussels on Sunday, with Belgian police firing tear gas and water cannon at demonstrators.
The rally descended into violence after many of the protesters had left, with some of the stragglers smashing cars and setting bins on fire.
Although Belgium has stopped short of locking down like Austria, it has ordered people to work from home where possible and extended mask requirements across the country.
In the Netherlands, where the government has ordered businesses to close early and limited social visits, more than 130 people were arrested during three nights of unrest.
Dutch Prime Minister Mark Rutte on Monday described the riots as "pure violence under the guise of protest".
"I will never accept that idiots use pure violence," he told Dutch media.
In Leeuwarden, police vans were pelted with rocks on Sunday and black-clad groups chanted and set off flares. Police used batons to disperse a crowd in Enschede.
In Denmark, about 1,000 people expressed their anger at the return of vaccine certificates for civil servants. There was further public anger in Zagreb, the capital of Croatia.
Meanwhile, France sent dozens of elite forces to its Caribbean island territory of Guadeloupe after arson and looting erupted despite an overnight curfew.
The WHO said last week that Europe was the only region in which Covid-19 deaths were rising. The autumn surge of infections is overwhelming hospitals in many Central and Eastern European nations.
In Germany, where infection levels are at a record high, state leaders agreed new rules in which tougher measures will be triggered if the pressure on hospitals becomes too severe.
After Mr Spahn's stark comments, Chancellor Angela Merkel told party colleagues that the situation was "highly dramatic" and that current measures were not enough, party sources told AFP.
In the UK, which lifted nearly all restrictions in July, ministers have resisted calls to switch to a Plan B in which masks and vaccine checks could become compulsory.