Thousands of people have taken part in marches in Vienna against an annual ball that was expected to be attended by foreign far-right leaders.
The protesters are opposed to Austria's opposition Freedom Party (FPOe) holding its so-called Academics Ball in the city's imperial Hofburg palace.
Several people have been arrested after outbreaks of violence, police say.
The ball has in past years attracted far-right figures such as French National Front leader Marine le Pen.
Police say around 6,000 people took to the streets to rally against Friday's event.
Some protestors smashed shop windows and threw bottles, and several people were injured, police say.
Large parts of Vienna's old city had been cordoned off to prevent clashes between demonstrators and ball guests.
Journalists criticised police for declaring parts of the demonstration area off-limits for the media.
Natascha Strobl, a spokeswoman for the campaign group Offensive Gegen Rechts (Offensive Against the Right) told AFP news agency that the demonstration was "about halting the biggest gathering of Europe's extreme right elite".
The far-right FPOe is the third-biggest party in Austria, winning 21% of the vote in September's elections.
In a news conference on Tuesday, Johann Gudenus, leader of the Vienna branch of the FPOe, condemned violence towards the ball's attendees, calling it "the fascism of the 21st Century".
The organisation Jetzt Zeichen Setzen! (Take a Stand Now), which campaigns for remembrance of victims of Nazism, published an open letter this month against the ball signed by six Holocaust survivors.
"As survivors of the Nazi era, we are stunned that the Hofburg, which belongs to the republic, is still opening its doors to representatives of extreme-right organisations from Austria and Europe," it said.
The Academics Ball effectively replaces the controversial WKR Ball which ran as part of Vienna's annual ball season until two years ago. It was traditionally organised by student fraternities, which include far-right members from across Europe.
UN cultural body Unesco dropped the ball from a list of Austrian cultural traditions in 2012 over concerns about its links to far-right politics.
The ball attracted extra criticism that year as it took place on the same date as Holocaust Remembrance Day. However, organisers said the ball was always held on the last Friday in January.