By Geraldine Coughlan BBC correspondent in The Hague

A Bosnian Serb has denied charges of murder and torture of non-Serb prisoners at detentions camps in Bosnia in 1992 after appearing at the war crimes tribunal in the Hague.

del Ponte is pressing for the handover of Bosnian Serb suspects

Dusan Knezevic, 34, pleaded not guilty to 46 charges of the murder, persecution and torture and rape of Bosnian, Muslim and Croat prisoners at the notorious Omarska and Keraterm camps.

Thousands were held there after the Serbs took over north western Bosnia at the start of the conflict.

A former waiter, Mr Knezevic, is alleged to have been one of several so-called visitors to the camps who helped the guards to beat and kill detainees.

Handover calls

Prosecutors claim that physical and psychological abuse were common place at the camps, and that Bosnian, Muslim and Croat political and civil leaders and non-Serbs who were considered as extremists were especially targeted.

Hundreds, many whose identities are unknown did not survive.

The Bosnian Serb government passed a law last year on cooperation with the tribunal but so far has not handed over any suspects.

The tribunal's chief prosecutor, Carla del Ponte, is urging the government to step up efforts to send some of the 20 wanted Bosnian Serbs to the Hague including the top indicted criminals Radovan Karadzic and Ratko Mladic.

Mr Knezevic surrendered to the court last week.