Protestors were arrested in Vienna last night as around 6,000 people gathered in the streets to demonstrate against a ball held by the right-wing Freedom Party.
Police said around 12 people were apprehended as tensions boiled over and demonstrators damaged shops and police vehicles.
They were opposing the annual Academics’ Ball, which is seen by some as a magnet for the far-right fringe.
Freedom Party officials deny that, and say they are the target of left-wing extremists.
Police are being criticised for declaring parts of the demonstration area off-limits for journalists.
They said it was to protect reporters from injury but Austrian news organisations argued the decision restricted media freedoms.
Officials had shut off large sections of the inner city ahead of the ball in the imperial Hofburg palace, which is an annual flashpoint for clashes with leftist opponents of the event.
Controversially, police also banned everyone within the city's outer ring road from covering their faces, arguing it could prevent police from identifying potential troublemakers.
The head of the Freedom Party in Vienna, Johann Gudenus, told a news conference on Tuesday he defended the right of protesters to demonstrate but said this did not include the use of violence.
“That is the fascism of the 21st century,” he said.
His remarks recalled Freedom Party leader Heinz-Christian Strache's reported description of himself and other ball-goers as the “new Jews” after some visitors were intimidated by protesters at the 2012 Akademikerball, which was held that year on International Holocaust Remembrance day.
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.
In 1938, Nazi Germany annexed Austria, whose 200,000-strong Jewish population was wiped out in the Holocaust.
The ball has previously attracted such far-right luminaries as French National Front leader Marine le Pen.
Last year, nine protesters were arrested for civil disorder and two ball-goers were slightly hurt.
Additional reporting by AP and ReutersReuse content