Bosnia's full cooperation with the UN war crimes court is a key condition for joining a NATO program seen as a first step towards membership in the Alliance, German Defense Minister Peter Struck said while visiting Sarajevo Monday. "Germany is supporting the wish of Bosnia-Hercegovina to join the Partnership for Peace Program, but there are preconditions to be met, such as the cooperation with the UN war crimes tribunal" in The Hague, Struck told AFP. Struck, who spoke after meeting his Bosnian counterpart Nikola Radovanovic, added that surrender of some of the UN tribunal's top war crimes suspects -- notably Bosnian Serb wartime military chief Ratko Mladic -- would "advance to a great extent" Bosnia's chances to join the NATO program. Bosnia's application for NATO's Partnership for Peace Program was twice rejected last year due to lack of cooperation with the UN war crimes court. Bosnian Serb authorities, accused of obstructing the tribunal's work, have not arrested a single suspect since the end of Bosnia's 1992-95 war. The two most wanted Bosnian war crimes indictees, Mladic and political leader Radovan Karadzic, wanted for genocide over their role in the war, remain at large.