BELGRADE (Agencies) - Former Bosnian Serb President Radovan Karadzic, the man accused of masterminding the massacre of tens of thousands of Bosnian Muslims during the brutal Balkans conflict, has been arrested after more than 13 years on the run. Karadzic, accused of ordering the deadly siege of Sarajevo and some of the worst atrocities in Europe since World War II - including the 1995 massacre of thousands of Muslims in Srebrenica - was arrested by Serb authorities on a bus in the Serbian capital Belgrade on Monday night, his lawyer said. The capture of the so-called 'Butcher of Bosnia' was hailed as a landmark for international justice and for Serbia, whose new government has pledged to bring its wanted war criminals to justice as a condition of membership of the European Union. Karadzic, one of the world's most wanted men, was arrested on genocide charges while practising medicine under a fake name in Belgrade, officials said Tuesday. Despite his status as one of the most wanted men on the planet, Karadzic, 63, had been working in a medical clinic with only a false name and a beard to conceal his identity. "He was working and performing alternative medicine, making money that way," said Rasim Ljajic, the Serbian minister in charge of cooperation with the International Criminal Tribunal for the former Yugoslavia (ICTY) in The Hague. "He was very convincing in hiding his identity," said Ljajic, who held up a photograph of Karadzic with almost hippy-like long white hair and beard. Of all the ICTY fugitives, Karadzic was always the subject of the most fevered speculation about his whereabouts. He had last been seen in public in the eastern Bosnian town of Han Pijesak in July 1996, and was previously thought to have hidden away in Serb-controlled parts of Bosnia, Montenegro and Serbia, or even Russia. Following his capture, he was questioned by a magistrate who concluded "all conditions have been met for his transfer" to The Hague for trial, said Serbia's war crimes prosecutor. The arrest of Karadzic means there are only two more fugitives of the UN court at large. They are his former military commander Ratko Mladic, 65, and Goran Hadzic, 49, a former Serb politician wanted for "ethnic cleansing" in Croatia. Karadzic's arrest took place two weeks after the formation of a new pro-EU membership government dominated by President Boris Tadic's pro-Western Democratic Party. It also came only four days after Sasa Vukadinovic, close to the Democrats, became the head of Serbia's police intelligence agency, replacing an official aligned with former hardline nationalist prime minister Vojislav Kostunica. While Muslims staged noisy celebrations on Sarajevo's streets, Serbs in Karadzic's wartime stronghold of Pale expressed their anger and disappointment. Karadzic's lawyer Svetozar Vujacic said his client would appeal the decision to transfer him to The Hague, while his brother stated Karadzic. In the bitter war against Bosnia's Muslim-led government, Karadzic is said to have authorised "ethnic cleansing" in which more than a million non-Serbs were driven from their homes in villages where they had lived for generations. The expulsions were accompanied, according to foreign observers, by widespread killings and up to 20,000 rapes in a calculated programme of terror. EU foreign policy chief Javier Solana said he hoped Karadzic's arrest would now help unblock a key EU-Serbia accord. The Netherlands, which backed by Belgium is the last EU member country to hold out on the application of the EU rapprochement agreement, urged Serbia to continue cooperating with the UN tribunal. Karadzic's arrest "proves that Serbia is able to catch war criminals (but) I will continue to insist towards Belgrade on the arrest of Ratko Mladic and Goran Hadzic," said Dutch Foreign Minister Maxime Verhagen. Karadzic was a close ally of former Yugoslav president Slobodan Milosevic, who died in custody in The Hague in 2006, before the ICTY delivered a verdict in his case.