She was referring to the list of criteria for ex-Yugoslav aspirant countries to join the bloc which includes an obligation for them to allow judges of the International Criminal Tribunal for the former Yugoslavia (ICTY) to bring their nationals to trial.

"Ninety percent of those accused in custody now are direct results of EU conditionality. It is a unique incentive. Both a carrot and a stick," she argued.

Ms del Ponte believes the same tool could prove crucial in attempts to get hold of the four remaining fugitives - all believed to be hiding in Serbia - including Bosnian Serbs Radovan Karadzic and Ratko Mladic.

The chief prosecutor is optimistic about the will of the new Serbian government to co-operate with the Hague, but she says the EU should notsign the Stabilization and Association Agreement - a waiting room for EU candidate country status - with Belgrade before General Mladic is caught.

On Karadzic, the former political leader of the separatist Republika Srpska during the 1992-95 war in Bosnia, she said that "no one seems to be looking for him. It seems as if he has disappeared from radar screens" although his new books of poetry still get published in Serbia.

"If Mladic was arrested, it would be easier to smoke out Karadzic," Ms del Ponte suggested, adding that her key concern is that the hunt goes on despite the projected closure of the Hague tribunal in 2010. "They can't have an illusion they'll escape justice by just waiting till the court is over."

The Kosovo question

MEPs participating in Tuesday's debate questioned her recent remarks made at the UN about the possible negative implications of an early deal on Kosovo independence for capturing the four Serbian fugitives.

Ms del Ponte voiced worries that the patronage of the international community "towards one side became a serious obstacle to the process of justice" in the case of Kosovo Albanians accused of atrocities against the Serb minority in the region.

The prosecutor argued "some members" of Kosovo's police had threatened prosecution witnesses in the case of Ramush Haradinaj, a former Kosovo prime minister and rebel leader facing the tribunal's accusations of criminal acts against Serbs.

This led to their refusal to be witnesses in the Hague due to fears their lives were in danger.

"It is sometimes perceived as the ICTY's failure that it has not contributed to stability and reconciliation in the region. Such expectations were basically overestimated," Ms del Ponte said.

"The ICTY contributed to the understanding of what happened on the ground during the war. It didn't and couldn't bring consensus among people."