Bosnian Muslim women cry during a ceremony in the eastern Bosnian town of Visegrad Saturday organized to commemorate thousands of Bosnian Muslims killed by Serb troops commanded by Ratko Mladic at the start of Bosnia's 1992-95 war. (AP) BELGRADE: Serbia vowed on Saturday to track down those who helped Bosnian Serb war crimes suspect Ratko Mladic evade justice for so long, as fresh details emerged of his arrest after 16 years on the run. “We will continue to pursue all those who have helped Mladic and other fugitives evade justice,” Serbian war crimes prosecutor Vladimir Vukcevic said. “By hiding Mladic they have caused serious damage to this country. Hiding fugitives from the Hague tribunal is a serious crime,” he added. Officials also said Serbia was stepping up security ahead of a planned protest by ultra-nationalists on Sunday against Mladic's arrest, amid fears the demonstration could lead to violence. Mladic, accused of masterminding the 1995 Srebrenica massacre and other atrocities during the 1992-95 Bosnian war, was arrested Thursday and is set to be transferred next week to the International Criminal Tribunal for the former Yugoslavia (ICTY) in The Hague. Judges are expected to rule Monday on an appeal against his transfer to the court, where he faces charges of war crimes, genocide and crimes against humanity. A judge on Friday ruled he is fit to face trial despite pleas from his lawyer and family that Mladic is not strong enough to be transferred. His capture came amid many questions as to how Europe's most-wanted man was able to evade his pursuers for so long. Serbian authorities insist there was no collusion but the opposition here has suggested that some in the security forces in Serbia - where many still see Mladic as a war hero - were involved in protecting him. President Boris Tadic told the BBC on Friday that authorities would leave no stone unturned in their search for those who sheltered Mladic. Tadic promised a “full and complete picture” of the network. Interior Minister Ivica Dacic meanwhile said security had been stepped up after the ultra-nationalist Radical Party (SRS) called for a massive protest in Belgrade on Sunday. “The police will not use force in advance ... only if there is a drastic violation of public peace and order,” Dacic told journalists. “Security measures have been increased to a higher level,” he said, including around state buildings and embassies. After the arrest of Bosnian Serb wartime political leader Radovan Karadzic in July 2008, thousands of ultra-nationalists violently protested in Belgrade, leaving one dead. – Agence France