Police fired tear gas to break up scuffles with youths during a demonstration by hardline Serbian nationalists in support of war crimes suspect Radovan Karadzic.

Clashes broke out when several dozen youths linked to hooligan groups threw flares, stones and garbage cans at riot police. Security forces responded with baton charges and rounds of tear gas.

Around 45 people were treated for light injuries in Belgrade hospitals, 25 of them policemen. One Spanish and one Serb journalist were also hurt.

Some 10,000 people, many bused in from rural nationalist strongholds, gathered in downtown Belgrade for the rally to show their support.

The protest came after Karadzic's legal team tried to block his extradition to an international tribunal.

The leader of the Bosnian Serbs in the 1992-95 Bosnia war, who is indicted for genocide, was arrested last week in Serbia.

He had been on the run for 11 years, most recently living under an assumed name as a bearded, long-haired alternative healer.

He is now in a Belgrade prison awaiting transfer to the United Nations war crimes tribunal in The Hague.

Karadzic, along with his military chief Ratko Mladic, is indicted for the massacre of 8,000 Bosnian Muslims at Srebrenica and the 43-month siege of Sarajevo, where more than 11,000 people died from shelling, sniper fire, malnutrition and illness.

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