Serbia on Wednesday arrested Stojan Zupljanin, a Bosnian Serb police chief accused of genocide and atrocities against Muslims and Croats in the Bosnian war, reducing the number of war crimes fugitives the world demands of it to three, according to dpa. Zupljanin, 56, would be transferred to the custody of the International Criminal Tribunal for the former Yugoslavia (ICTY) within three weeks, the Serbian prosecutor's spokesman Bruno Vekaric said. During the 1992-95 Bosnian war, Zupljanin was a prominent member of Radovan Karadzic's Bosnian Serb authorities which had organized the 1995 massacre of 8,000 Srebrenica Muslims. The arrest and delivery of suspects to The Hague-based ICTY is the key condition for Serbia to remain on track out of the isolation imposed on it over its role in the Balkan conflicts. Slovak diplomat Miroslav Lajcak welcomed the "long-awaited" arrest, saying the recent actions of the international community had helped create the conditions leading to his arrest. "Pressure on their (fugitives') support networks will continue," Lajcak said in a statement. ICTY prosecution spokeswoman Olga Kavran said "three other indictees would soon follow Zupljanin." The European Union also welcomed Zupljanin's arrest as a boost to Serbia's EU membership prospects, but warned that the remaining suspects must also be caught. "I welcome the news confirmed by ICTY that Stojan Zupljanin has been arrested," the EU Enlargement Commissioner Olli Rehn said in a statement. "It is an important step towards full cooperation with the ICTY, which is key to bringing justice and lasting reconciliation in the Western Balkans region," he said. The EU signed a pre-membership deal with Serbia in April despite objections from several countries over Belgrade's failure to fully cooperate with the ICTY. Serbia is not likely be allowed to progress further until it delivers at least two more key war crimes suspects who remain at large. Its reluctance to arrest the war criminals, some of whom are regarded as heroes by the nationalists, has cost Serbia both in terms of money in frozen aid and time lost on approach to EU membership since Slobodan Milosevic's regime fell in 2000. Zupljanin, the fugitive former wartime Bosnian Serb internal security chief, was arrested near Belgrade a week after ICTY chief prosecutor Serge Brammertz blasted Belgrade over its failure to bring suspects to justice despite having them "at fingertips." It came also less than two weeks after the international administrator in Bosnia, Miroslav Lajcak, cracked down on a group of alleged collaborators who fed Zupljanin information, helping him escape earlier raids. Zupljanin was a high-ranking police and secret service official in the wartime administration of Radovan Karadzic, which led the self-proclaimed Serb Republic during the bloody conflict. He was also Karadzic's special advisor. The ICTY raised a 12-count indictment against him for complicity in genocide, crimes against humanity and violations of laws and customs of war and breaches of the Geneva Convention. Karadzic, who remains at large along with his military commander Ratko Mladic, is held responsible for crimes such as the Srebrenica massacre and 30 months of shelling and sniping of the capital Sarajevo. The final fugitive the international community is pressing Belgrade to arrest is Croatian Serb leader Goran Hadzic. Karadzic is believed to be hiding in Bosnia despite a massive international peacekeeping and policing presence that has been in the country since the US brokered a peace deal to end the conflict in late 1995. Serbian officials have on many occasions indicated they want to work with the ICTY and bring the issue to its conclusion. "This arrest shows clearly that we are seriously cooperating and there is the political will for full cooperation," special war crimes prosecutor Vladimir Vukcevic told TV B92. Belgrade's former minister in charge of relations with the ICTY, Rasim Ljajic, said the Zupljanin arrest proved "Serbia is doing everything it can to meet its obligations to The Hague tribunal."