BELGRADE, Serbia (CNN) -- Former Bosnian leader Radovan Karadzic will fight extradition from Serbia on war crime charges, his lawyer said Tuesday.

Lawyer Sveta Vujacic also disputed Serbian accounts of Karadzic's arrest alleging the man known as the 'Butcher of Bosnia' was seized Friday and held in secret for three days.

Karadzic, 63, is 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 8,000 Muslims in Srebrenica

Vujacic said Serbian authorities were not telling the truth about Karadzic's arrest.

"Nobody seems to know who arrested him and where he has been since last Friday at 21:30 hours, when he was arrested," he said.

"He just said that these people showed him a police badge and then he was taken to some place and kept in the room. He was blindfolded ... he was kept in some room ... and that is absolutely against the law what they did."

Vujacic said he will launch criminal proceedings in addition to an appeal against Karadzic's transfer to the International Criminal Tribunal for the Former Yugoslavia (ICTY) at The Hague. Watch Karadzic's lawyer slam arrest »

A judge has three days to prepare for his transfer. Prosecutor Vladimir Vukcevic said Karadzic has the right to appeal that transfer within those three days.

Serb authorities say Karadzic -- in disguise and using a false identity -- was working at a medical practice in Belgrade prior to his arrest.

Karadzic was so convinced of his disguise he regularly contributed to a health magazine as he brazenly built up his profile as an alternative medical practitioner, The Associated Press reported.

Goran Kojic, editor in chief of Serbia's "Healthy Life," released new images of the former leader hidden behind an enormous white beard, long hair and spectacles, identifying one of the world's most wanted men as a regular contributor.

"It never even occurred to me that this man with a long white beard and hair was Karadzic," a shocked Kojic said, according to The Associated Press.

At a news conference in Belgrade on Tuesday, authorities displayed another recent picture of Karadzic that showed him with short white hair, a long white beard and glasses. Before he went on the run, Karadzic was clean-shaven with a mop of salt-and-pepper hair.

Serbian minister Rasim Ljajic said Karadzic was using false documents giving him the name of "Dragan Dabic" and a non-Serbian identity at the time of arrest.

"It wasn't expected at all that this would ever happen to Radovan Karadzic -- that he would ever be caught in this way," said Ljajic, president of the National Council for Cooperation with the Hague Tribunal. Watch CNN's Christiane Amanpour chronicle the life of Karadzic »

The arrest has been 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.

"We understand that there is an absolute determination by the state to finish this job," Vukcevic said.

Karadzic's arrest earlier drew jubilation in the streets of Sarajevo, the Bosnian capital, which Bosnian Serb forces had shelled heavily during the war, and a small protest from ultra Serb nationalists in front of Belgrade's heavily guarded war crimes court. Watch protests in Serbia »

Karadzic's brother Luka told reporters that he had seen the former leader in custody.

"Karadzic is in good health. He has lost a lot of weight, he is full of optimism," he said.

Karadzic -- last seen in public in 1996 -- was the Bosnian Serb political leader during the 1992-1995 war that followed Bosnia-Herzegovina's secession from Yugoslavia.

While president of the so-called Serbian Republic of Bosnia-Herzegovina, Karadzic's troops were reported to have massacred hundreds of thousands of Muslims and Croats during a campaign of "ethnic cleansing." Follow a timeline on Karadzic »

Early estimates of the death toll from the 3-year war ranged up to 300,000, but recent research reduced that to about 100,000.

Vladimir Petrovic, the charge d'affairs at the Serbian Embassy in Washington, said the arrest showed his country's commitment to accounting for its past.

EU foreign affairs chief Javier Solana said: "I think it is very important that Radovan Karadzic will be in front of International Tribunal having a fair trial."

CNN's Alessio Vinci in Belgrade said few in the city believe Karadzic will get a fair trial but the size of the demonstrations is a sign that few care. He said those supporting closer ties with the West are happy at the arrest.

Karadzic's arrest leaves former Gen. Ratko Mladic, the Bosnian Serb military commander, as the top-ranking war crimes suspect still at large.

"Today, I can tell you that I feel kind of good," said Zlatko Lagumdzija, a former Bosnian prime minister wounded during the siege. He said the arrest could offer "a chance for new thinking" in Bosnia, still grappling with the scars of war.

Karadzic, a one-time psychiatrist and self-styled poet, declared himself president of a Bosnian Serb republic when Bosnia-Herzegovina seceded from Yugoslavia in 1992.

The Bosnian Serbs, backed by the Serb-dominated Yugoslav military and paramilitary forces, quickly seized control of most of the country and laid siege to Sarajevo, the capital.

During the conflict that followed, the Serb forces launched what they called the "ethnic cleansing" of the territories under their control -- the forced displacement and killings of Muslims and Croats. See a map of the Balkans today »

He was removed from power in 1995, when the Dayton Accords that ended the Bosnian war barred anyone accused of war crimes from holding office.

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