BELGRADE, July 29 (RIA Novosti) - Supporters of Radovan Karadzic, the former Bosnian Serb leader awaiting extradition to The Hague on charges of war crimes, are to hold a demonstration in the centre of Belgrade on Tuesday evening.

The protest in the Serbian capital is scheduled to start at 7:00 p.m. (17:00 GMT) and has been organized by the Radical Party with the support of the Democratic Party of Serbia, led by former prime minister, Vojislav Kostunica.

According to Radical Party leader, Aleksandar Vucic, "tens of thousands of people" are expected to attend. The demonstration will be the first major show of force by the nationalists since Karadzic's arrest was announced on July 21.

Vucic has called for a peaceful march to demonstrate the "unity of all the free people of Serbia." Supporters are being bused in from all over Serbia and Serbian parts of Bosnia. The last large-scale nationalist protest in Belgrade, against the recognition of Kosovo's independence by many Western countries in February, ended in looting and an attack on the U.S. embassy.

Karadzic, 63, faces a total of 11 charges at the UN tribunal in The Hague, including genocide and conspiracy to commit genocide. He is also accused of being behind the 1995 massacre of 8,000 Muslim men and boys in Srebrenica - the worst mass murder since the end of WWII - and the 1992-1995 siege of Sarajevo, during which 10,000 people died.

His arrest, which came only two weeks after Serbian President Boris Tadic's pro-Western government came to power, has been welcomed by Western countries, and seen as an important step in Serbia's bid to join the European Union. The arrest of Karadzic was one of the conditions set by the EU for Serbian membership of the organization.

The former Bosnian Serb leader had spent more than a decade on the run before his arrest. He had been living in Belgrade under an assumed identity, sporting a huge white beard and practicing alternative medicine.

Karadzic's lawyer, Svetozar Vujacic, said that he had posted an appeal against his client's extradition to The Hague at the last possible moment from a distant post office in Bosnia in an attempt to keep his client in Serbia until today's rally. The attempt would seem to have been successful.

Vujacic said last week that Karadzic would defend himself at the UN tribunal in The Hague.