BELGRADE, August 16, 2008 (AFP) - A supporter of Bosnian Serb war crimes suspect Radovan Karadzic critically injured in clashes with riot police in Belgrade last month has died, an ultra-nationalist politician said Saturday.

Ranko Panic, who was from Croatia, suffered injuries to his abdomen on July 29 when police cracked down on demonstrators protesting Karadzic's transfer to the UN war crimes tribunal, said Radical Party leader Aleksandar Vucic.

'Those in power must declare who is responsible for Ranko Panic's death', Vucic was quoted as saying by the Beta news agency, adding that an autopsy would be held Monday.

Panic's death could not be confirmed through other sources.

More than 70 people were injured, just over half of them police officers, when demonstrations against Karadzic's transfer to the International Criminal Tribunal for the former Yugoslavia turned violent.

Karadzic was sent off to The Hague the following day to stand trial on charges of genocide, war crimes and crimes against humanity arising from the 1992-95 war in Bosnia-Herzegovina.