A former Bosnian Serb Army security officer indicted by The Hague-based war crimes tribunal for the 1995 Srebrenica massacre is set to voluntarily surrender to the U.N. court, the Serbian government said Friday. Colonel Vujadin Popovic will travel to The Hague on Thursday accompanied by high-ranking Belgrade official Zoran Loncar. Popovic is the 13th war crimes suspect to surrender in Serbia since October following the massive international pressure on the Belgrade government to end more than a decade-long dispute over the whereabouts of indicted fugitives. ---SP 2259 Local Time 1959 GMT