Bosnian Serb military commander Ratko Mladic returned to a United Nations court on Tuesday to appeal his 2017 conviction for genocide and crimes against humanity during the Yugoslav Wars.Mladic is serving a life sentence after being found guilty of overseeing the slaughter of 8,000 Muslim men and boys at Srebrenica in 1995 and attacking and murdering civilians during the 43-month siege of the Bosnian capital Sarajevo. Trial judges ruled he was responsible for massacres of Bosnian Muslims and "ethnic cleansing" campaigns as part of a plan to forge a Greater Serbia out of parts of the former Yugoslavia, together with Bosnian Serb leader Radovan Karadzic and former Serb politician Slobodan Milosvic. He was the commander of Bosnian Serb forces during the 1992-95 war that was part of Yugoslavia's breakup.At the start of two days of hearings, Presiding Judge Prisca Nyambe said Mladic has put forward nine grounds of appeal, asking for acquittal or a retrial."The prosecution responds that Mr. Mladic's appeal should be rejected in its totality," she said in opening remarks.Mladic, 77, appeared wearing a facemask which he removed after a few minutes. The proceedings are being broadcast by video due to the coronavirus pandemic. Mladic's lawyers have sought to delay the appeal, arguing that the former general is in poor health.Mladic was convicted of 10 out of 11 charges at trial and prosecutors are seeking an additional genocide conviction.Prosecutors say Mladic's sentence should be upheld, and he should also have been convicted of the 11th charge, genocide against Bosniaks and Croats in five municipalities of Bosnia in 1992.Mladic's appeal is being held at a UN court in The Hague set up to hear appeals and remaining cases from the former Yugoslav Tribunal, which closed in 2017.Mladic will be allowed to address the court for 10 minutes on Wednesday. Judges have yet to set a date for a decision, likely to be sometime in 2021.