The Hague - The convicted Bosnian Serb war criminal, Dusan "Dusko" Tadic, has appealed against a 20-year prison term handed down by the UN war crimes court in The Hague. The court said yesterday that Tadic's lawyers argued that there had been "errors of law" which invalidated the decision and "errors of fact" which had led to a miscarriage of justice. Tadic (41), dubbed "the monster of Kazarac", was found guilty in May on 11 counts of war crimes while he was serving as a guard in 1992 at the Serb-run detention camp for Muslims at Omarska. He was acquitted of 13 murders, five beatings, abuse of prisoners and inhumane acts, including the sexual mutilation of one prisoner.