With the arrest of Bosnian Serb leader Radovan Karadzic, UN prosecutors are likely to seek a speedy trial to avoid the lengthy proceedings that have dogged the Hague tribunal in the past.
After more than a decade on the run, Mr Karadzic, 63, was arrested last night in Belgrade to face charges of genocide related to Europe's worst atrocities since World War II.
He is expected to be moved later this week to the Netherlands to face trial at the International Criminal Tribunal for the former Yugoslavia, created 15 years ago to prosecute crimes committed during the 1992-95 Bosnia war.
Officials hope a marathon trial, such as that of Slobodan Milosevic, will be avoided. That trial ended prematurely two years ago with the death in custody of the former Yugoslav President.
During Mr Milosevic's four-year trial, prosecutors called nearly 300 witnesses.
It is thought prosecutors will need to deliver a speedy and efficient trial this time as the tribunal faces a deadline to wrap up proceedings.
The Yugoslavia tribunal is due to close in 2010.
However, there is a chance this may be extended with the arrest of Mr Karadzic and hopes that Ratko Mladic, the last major fugitive, will be arrested.
News of the arrest of Radovan Karadzic brought people out onto the streets of Sarajevo overnight to celebrate the capture of the man charged with authorising the killing of 11,000 of their fellow citizens.
Mr Karadzic had been under surveillance in Serbia for several weeks after a tip-off from a foreign intelligence service.
He did not resist arrest.
Mr Karadzic had been working in a medical clinic under a false name and had tried to conceal his identity with a white beard.
He was using false documents with the name Dragan Dabic, according to the minister in charge of cooperation with the International Criminal Tribunal for the former Yugoslavia, Rasim Ljajic.
His arrest was one of the main conditions of Serbian progress towards EU membership.
It came on the eve of a meeting of EU foreign ministers scheduled to discuss closer relations with Belgrade following the formation of a new pro-Western government.
Decisive step
UN Secretary-General Ban Ki-moon praised Serbian authorities for taking a 'decisive step toward ending impunity' of those indicted for crimes in Balkan conflicts.
'This is a historic moment for the victims, who have waited 13 years for Mr Karadzic to be brought to justice,' he says in a statement released by the UN.
The former UN high representative in Bosnia, Paddy Ashdown, welcomed the arrest and said it could accelerate the capture of his number two.
Lord Ashdown said the arrest of Mr Karadzic, a key ally of former Serbian strongman president Slobodan Milosevic, was significant and an important day for Serbia.
Mr Karadzic went underground more than a year after the 1995 Dayton accords that ended the war in Bosnia and NATO deployed a huge force of peacekeepers in early 1996.
Alleged sightings were rare. He was said to be hiding in monasteries, disguised, shuttling among remote hideouts with the help of a network of loyalists.
His arrest leaves two war crimes suspects still wanted by the Hague tribunal. But it should be enough to secure Serbia closer ties with the EU and possibly the status of EU membership candidate state this year.
Mr Karadzic was indicted along with his army commander, General Ratko Mladic, for genocide at Srebrenica, where some 8,000 unarmed Bosnian Muslim males were rounded up, murdered and bulldozed into mass graves in July 1995.
