[JURIST] A former Serbian soldier admitted in a special high-security court in Belgrade on Tuesday that he participated in the November 1991 execution of about 200 Croatian prisoners of war [BBC backgrounder] at a pig farm. The testimony by Ivan Atansijevic was the first admission by one of the 16 defendants who are being tried [JURIST report] for the execution of POWs captured in a successful Serbian assault on the eastern Croat town of Vukovar during the breakup of the former Yugoslavia. Three alleged leaders of the massacre are being tried [JURIST report] by the International Tribunal for the former Yugoslavia [official website], which tries top civilian and military leaders, while the special court in Belgrade is dealing with the 16 other lower-level suspects. The Belgrade trial is seen as a key test of the ability of Serbia's post-Milosevic judiciary system to deal with war crimes cases committed by Serbs during the Yugoslavian civil war. AP has more.