Serb ultranationalist Vojislav Seselj set fire to EU and NATO flags in Belgrade on Thursday as he insisted he would not attend the verdict in his war crimes trial at The Hague later this month.
The International Criminal Tribunal for the former Yugoslavia (ICTY) allowed Seselj to return to Serbia in 2014 for cancer treatment pending its judgement over charges of crimes against humanity, but he has since vowed not to return.
The 61-year-old is accused of leading Serb volunteers to "cleanse" large parts of Bosnia, Croatia and Serbia's northern Vojvodina region during the Balkans wars which erupted amid the break-up of Yugoslavia in the 1990s.
Judges at the ICTY have ordered that Seselj should appear before them on March 31 to hear its judgement in person, and he was due to appear at Serbia's war crimes court in Belgrade on Thursday over the request.
But the session was postponed for procedural reasons, and Seselj instead burnt the EU and NATO flags outside the building in front of around 100 supporters.
Seselj surrendered to the ICTY in 2003, and his trial ran from 2007 to 2012.
Since his release for medical treatment, he has resumed his fiery nationalist rhetoric and repeatedly lashed out at the tribunal, vowing neither to return for his sentencing nor to serve any time.
Leader of the far-right Serbian Radical Party, he intends to run for parliament in the country's election in April.
He faces three counts of crimes against humanity, including persecution, deportation and forcible transfers, and six other charges including murder and torture.
ICTY presiding judge Jean-Claude Antonetti last month ordered the Serbian authorities "to make every provision needed to ensure that the accused appears on the day that the verdict is pronounced".
War crimes judges have also accused Belgrade of failing to cooperate with the tribunal by not arresting three suspects in a separate contempt case arising out of Seselj's trial.
More than 130,000 people died and millions of others were left homeless during the Balkans wars.