United Nations prosecutors are seeking two separate trials for ex-Bosnian Serb military chief Ratko Mladic, in an attempt to speed up the prosecution and ensure that a verdict is handed down to the aging war crimes suspect.

The chief prosecutor for the U.N. war crimes tribunal for the former Yugoslavia says he wants Mladic to first be tried for his alleged role in the 1995 Srebrenica massacre, in which 8,000 Muslim men and boys were killed.

Mladic would then be tried on other charges, including the 44-month siege of Bosnia's capital city, Sarajevo, in which 10,000 people died.

U.N. prosecutors expressed concern on Wednesday that Mladic's health may deteriorate before an all-encompassing trial is completed.

Mladic was arrested in Serbia in May after being a fugitive for 16 years. During his first court appearance in June, Mladic described himself as “gravely ill.”

Last month, Mladic appeared at The Hague to face war crimes charges, but was ejected after disrupting the proceedings. A judge entered a “not guilty” plea on all 11 charges against him.

Mladic is the last of three top Serbian leaders wanted for war crimes. Bosnian-Serb wartime leader Radovan Karadzic was captured in 2008 and his trial is underway. Former Serbian president Slobodan Milosevic died in custody in 2006 before his trial ended.

If convicted, Mladic could be sentenced to life in prison.