Serbia could become EU candidate in 2009

Mr Barroso stressed however that his statement did not represent a time commitment, insisting that Serbia's EU integration "cannot be a calendar-driven process, but should be a reform-driven one."

For his part, Mr Tadic said he hoped his country would obtain the candidate status "as soon as possible" and pledged to continue with the necessary reforms.

Serbia has previously expressed hopes to join Turkey, Croatia and Macedonia as official EU candidate as early as next year, and to become a full member by 2014.

But the EU considers that Belgrade has still a lot to do as far as economic and political reforms are concerned, and also wants the country to co-operate fully with the International Criminal Tribunal for the former Yugoslavia (ICTY) – notably by arresting the remaining war crimes suspects – before allowing it a step closer to the EU.

Unfreezing the pre-accession agreement?

In July, Serbia announced the arrest of former Bosnian Serb leader Radovan Karadzic after he had been on the run for more than ten years, having been charged with genocide, war crimes and crimes against humanity.

The arrest of Mr Karadzic was largely hailed in the EU and on Wednesday, Mr Barroso reiterated that it had been a "historic moment" for Serbia and "a milestone" for its EU ambitions.

He encouraged the 27 EU member states to "acknowledge" and reflect that by for instance implementing the trade-related part of a pre-accession agreement signed with Belgrade in April.

At the time, the EU decided to sign a Stabilisation and Association Agreement (SAA) with Serbia in a bid to send a political message to the country which was on the eve of elections seen as decisive for its EU future.

But at the insistence of the Netherlands and Belgium, member states decided they would refrain from implementing the document until Belgrade's co-operation with the UN war crimes tribunal in the Hague would judged to be sufficient.

UN prosecutor Serge Brammertz is to visit Belgrade next week to meet Serbian officials and discuss with them cooperation with the ICTY in the light of Mr Karadzic's arrest.

He will then brief EU foreign ministers during their meeting on 15 September.

Mr Tadic said his country was hoping for a positive result from Mr Brammertz's visit and stressed it was doing its best to arrest the two remaining fugitives, in particular high-profile war crimes suspect Ratko Mladic.

Serbian foreign minister Vuk Jeremic went further, saying he hoped his EU counterparts would in the light of the most recent events agree to ratify the SAA during their 15 September meeting.

"We have grounds to be optimistic," he was quoted as saying by DPA news agency after a meeting with EU foreign policy chief Javier Solana.

During their first meeting in the immediate aftermath of Mr Karadzic's arrest, EU foreign ministers stopped short of offering Belgrade any concrete concessions, calling on it to deliver Mr Mladic and former Croatian Serb rebel leader Goran Hadzic first.