Former Bosnian Serb leader Radovan Karadzic was taken to a prison cell in The Hague on Wednesday to face trial at a U.N war crimes tribunal on charges of genocide during the 1992-95 Bosnia war.

Karadzic, arrested near Belgrade last week, was flown out of Serbia by plane at night under tight security. Shortly after dawn, he was whisked from Rotterdam airport to the Scheveningen detention centre near The Hague.

He will appear before the tribunal for the first time at 4 p.m. (3 p.m. British time) on Thursday, and will be asked to enter a plea to the charges against him, the court said.

"His arrest is a major achievement of Serbia's cooperation with the U.N. security council," Prosecutor Serge Brammertz told reporters at the International Criminal Tribunal for the former Yugoslavia.

The trial was likely to begin in a few months, he added.

The only higher ranking official to be brought before the tribunal for crimes during the Balkan wars was Karadzic's former ally, Serbian leader Slobodan Milosevic, who died in 2006 at the detention centre months before a verdict was due at his trial.

Brammertz said he was confident Karadzic's trial would be efficient and successful, but noted two fugitives were still on the run after the Balkan wars of the 1990s. They include the Bosnian Serb wartime commander, General Ratko Mladic.

Karadzic's delivery to The Hague was key to Serbia securing closer ties with the European Union and his arrest was seen as a pro-Western signal by the new government sworn in this month.

His arrival at The Hague is expected by the Serbian government to defuse tension in Belgrade over his arrest and unlock EU trade benefits.

"The arrest by the Serbian authorities of Mr. Karadzic, then his transfer, mark an important step in the process of reconciliation in the western Balkans and in the rapprochement between Serbia and Europe," the EU Presidency, France, said in a statement, and called on Serbia to "continue on this path" and capture the last two remaining fugitives.

GENOCIDE CHARGES

Karadzic faces two charges of genocide over the 43-month siege of Sarajevo and the 1995 massacre of some 8,000 Muslims at Srebrenica, the worst atrocity in Europe since World War Two.

His lawyer in Belgrade has said Karadzic, 63, believes he will be cleared of genocide and will defend himself.

He will receive a medical examination and meet legal officials at the detention centre - standard practice for new detainees - and be assigned an en suite cell, identical to that occupied by Milosevic.

Milosevic spent his last five years at the centre and was found dead in his 15-square-metre cell due to heart failure, which Brammertz's predecessor described as a "total defeat".

Asked whether Karadzic's trial would draw on the lessons of the Milosevic trial, which lasted four years, Brammertz said: "We are fully aware of the importance of efficiency."

Karadzic was arrested after 11 years on the run. He was most recently living under an assumed name, had grown a flowing beard and long-hair, and was working as an alternative healer.

On Tuesday, some 10,000 hardline Serb nationalists, many brought by bus from rural nationalist strongholds, showed their support for Karadzic in Belgrade, chanting his name and holding up giant banners with his picture.

Clashes broke out when several dozen youths linked to hooligan groups threw flares, stones and garbage cans at riot police. Some 70 people, most of them policemen, were wounded.

Relatives have said Karadzic is in good spirits and preparing his defence. He has had two suits delivered for his court appearance, one light, one dark.