Updated

Austrian police say up to 2,700 officers will be on duty for a right-wing ball in Vienna, in an effort to ensure that violent protests will not be repeated.

The annual Akademikerball in the Austrian capital's ornate Hofburg palace is a fixture for members of Austria's right-wing Freedom Party, its supporters and like-minded guests from elsewhere in Europe.

Past participants have included France's Marine Le Pen, Belgium's Filip Dewinter, and Russia's Alexander Dugin.

Guest lists are not published and no prominent non-Austrian populist is known to be attending Friday's ball this year.

But focus on the event has grown with Donald Trump's White House victory and the strength of Europe's populists. In Austria, polls regularly show the Freedom Party with the most voter support.