Former Bosnian Serb leader Radovan Karadzic has started his appeal against a 40-year prison sentence for genocide and war crimes.
A UN tribunal in The Hague is hearing the two-day appeal.
The International Criminal Tribunal for the Former Yugoslavia (ICTY) convicted Karadzic in March 2016.
The ex-leader denounced the conviction as “political”. His lawyer says he did not get a fair trial but prosecutors want to increase his sentence to life.
Former Bosnian Serb army commander Ratko Mladic was sentenced to life in prison on similar charges in November 2017.
The Mechanism for International Criminal Tribunals (MICT) is hearing the appeal. The ICTY was dissolved in 2017.
A former psychiatrist, Karadzic was president of the Bosnian Serb entity Republika Srpska during the Bosnian War in the 1990s.
He was found guilty of 10 out of 11 counts of genocide, war crimes and other atrocities in the conflict, including planning the Srebrenica massacre of July 1995.
Bosnian Serb soldiers slaughtered nearly 8,000 Muslim men and boys in a “safe area” protected by Dutch peacekeeping forces for the UN.
Karadzic is also held responsible for the siege of Sarajevo, which lasted more than three years and led to the deaths of 10,000 civilians.
However, he was acquitted on one count of genocide relating to slaughter in seven other Bosnian towns.
Prosecutors believe the ICTY judges “erred in law and fact”, with chief prosecutor Serge Brammertz asking the judges to “correct the trial chamber’s errors” and imprison Karadzic for life.
Karadzic hid for years before his eventual arrest in Serbia in 2008.
He masqueraded as an expert in alternative medicine, and went by the name Dr Dragan David Dabic.