BELGRADE, Serbia (CNN) -- Former Bosnian Serb President Radovan Karadzic was en route to The Hague on Wednesday to answer war crimes charges, Serbian court officials said.
He faces 11 charges, including genocide, crimes against humanity and violations of the law of war stemming from the 1992-95 conflict in Bosnia-Herzegovina, while he led the breakaway Serb republic after its secession from Yugoslavia.
The onetime psychiatrist and aspiring poet was arrested last week after more than a decade as a fugitive.
Serbian authorities took steps to extradite Karadzic around 330 a.m. (9:30 p.m. ET Tuesday), sending black Range Rovers driven by masked men to a detention center where he was being held.
A white jet owned by the Serbian government took off from Belgrade International Airport about 4:15 a.m. local time (10:15 p.m. ET). It was expected to land at an airport in Rotterdam in The Netherlands -- the closest major airport to The Hague -- just after sunrise.
Two Dutch police helicopters have landed at Rotterdam International Airport, but it was unclear how authorities plan to transport Karadzic from the airport to a jail cell in The Hague.
He is likely to face a judge within a day or two at the International Criminal Tribunal for the Former Yugoslavia at The Hague.
Karadzic's extradition came hours after thousands of people rallied in his support, waving flags and chanting nationalist slogans, in Belgrade and decrying the prospect of his transfer to the International War Crimes Tribunal. Watch the rally »
"I'm here to support the movement of the people, to defend Karadzic from those cannibals in The Hague -- so-called judges," one man told CNN. "That is not judgment. That is inquisition."
CNN's Alessio Vinci said as many as 10,000 joined the rally but pointed out that earlier this year more than 250,0000 Serbs protested when Kosovo declared its independence.
A few dozen demonstrators clashed with police about a block from the square as the rally broke up, some setting fire to garbage cans. Police used tear gas to disperse them, and no injuries were reported.
Serbian ultranationalists organized the rally and view Karadzic as a hero of the Bosnian war. But Serbian President Boris Tadic reaffirmed his support for Karadzic's extradition, saying his government is "obeying our own laws."
"Those who are organizing and supporting this protest had the opportunity to change the law while they had a majority in parliament," said Tadic, whose government wants closer ties with the West. "They did not change this law because they did not want to or because they did not have enough political courage to change it."
The Bosnian war was Europe's bloodiest conflict since World War II and the longest of the wars spawned by the breakup of Yugoslavia in the early 1990s. Backed by the government of then-Yugoslav President Slobodan Milosevic, Bosnian Serb forces seized control of more than half the country and launched a campaign against the Muslim and Croat populations that introduced the term "ethnic cleansing" to the world. See how the former Yugoslavia broke into separate countries »
Karadzic was removed from power in 1995, when the Dayton Accords that ended the Bosnian war barred anyone accused of war crimes from holding office. Though he portrayed Serbs as victims, Karadzic is accused of responsibility for the massacre at Srebrenica, a U.N. "safe area" Serb troops overran in July 1995. Nearly 8,000 Bosnian Muslim men and boys were killed at Srebrenica, the worst European massacre since World War II.
Milosevic died in 2006 while on trial at The Hague. The highest-ranking figure to remain at large is Gen. Ratko Mladic, the Bosnian Serb military commander during the Bosnian war.
CNN's Alessio Vinci and Nic Robertson contributed to this report
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