"If they do not turn themselves, I call on members of the Republika Srpska police to arrest them if they are on the territory under the jurisdiction of the RS institutions," Cavic said in Banja Luka on Friday.
Cavic said he did not believe that Karadzic and Mladic were hiding in Bosnia-Herzegovina, but added that this did not exempt the Bosnian Serb Interior Ministry from the obligation to establish their whereabouts,
Cavic's call was issued against the backdrop of Wednesday's arrest of Croatian General Ante Gotovina in Spain.
The RS leader, like top officials in Serbia and Montenegro, believes that Gotovina's apprehension would lead to building up pressure on the authorities of the Bosnian Serb entity as well as Serbia and Montenegro to nab Karadzic and Mladic.
"We must counter that pressure so as to avoid being cornered and we must carry out our remaining obligations if it is possible, given that nobody either in the international community or in Serbia-Montenegro knows where Ratko Mladic is hiding," the chairman of the Serbian-Montenegrin council for cooperation with the ICTY, Rasim Ljajic, was quoted by Belgrade media as saying.
The state union's Foreign Minister Vuk Draskovic said that Gotovina's arrest opens the door for Croatia to the European Union and NATO while "Serbia-Montenegro, unfortunately, is further and further away from Europe".
Serbian President Boris Tadic congratulated the Croatian authorities on the arrest of the fugitive general and voiced hope that Serbia would reach such solutions and find war crimes indictees, wanted by the tribunal.