He was speaking to the press after visiting the Hrvoje Pozar Energy Institute.
Asked to comment on NATO's invitation to Serbia to join the Partnership for Peace programme despite lack of cooperation with the Hague war crimes tribunal, Mesic said the carrot and stick policy was always applied in such cases.
"This time they have been given the carrot, which means the possibility to join European processes, but they have to extradite the suspects wanted by the Hague tribunal, (Ratko) Mladic and (Radovan) Karadzic."
Mesic said that apart from those two Bosnian Serb wartime leaders, top generals from the former Yugoslavia, former military chief of staff Blagoje Adzic and defence minister Veljko Kadijevic, should also be tried, either in The Hague or before national courts.
"They should end up there. The executors, the lower-level officials, are being tried now, while those who planned the war, who incorporated the crime of genocide and war crimes into the war, remain outside, apart from Serbia's political leaders, who did end up in The Hague".
Speaking of his visit to Sarajevo later today, Mesic said it was not a visit by a state delegation but that he was invited to a play.
He added, however, that he would meet all three members of Bosnia and Herzegovina's collective presidency for talks on the current situation in Bosnia and its strategic goals, which he said were also Croatia's strategic goals -- Euro-Atlantic integration.