Belgrade and the European Union should start negotiations on Serbia's European integration which, alongside the Instrument for Pre-accession Assistance programme, will facilitate reforms in Serbia, said Pack.

It is possible, however, that failure to arrest and extradite Mladic and Hadzic will temporarily freeze the European integration process in the near future, she added.

Five EU countries have ratified Serbia's Stabilisation and Association Agreement, while two will do so soon, Pack said, voicing confidence that the German Bundestag, too, would ratify it together with the rest of the EU countries.

Asked about current Serbian-Bosnian relations, Pack said she was pleased that they had improved considerably, adding the EU's position on Bosnia and Herzegovina was very clear and that Serbia's should be too.

The EU has offered membership to Bosnia and Herzegovina as a united country and not to its entities. Therefore, threats of secession or other attempts to undermine Bosnia's sovereignty are unacceptable, Pack said, adding it was important that Serbia's political leadership shared the same goal and stood fully behind a united and multiethnic Bosnia and Herzegovina.

Speaking of expected Belgrade-Pristina talks, Pack said the dialogue should start as soon as possible, regardless of whether Kosovo held parliamentary elections this year or next February.

Still, Serbia and Kosovo must prepare the ground for negotiations so that experts on both sides could start talks on practical issues that are most important for the life of people in Kosovo, Pack was quoted as saying.

On Monday, EU foreign ministers asked the European Commission to start drafting an opinion on Serbia's application to be granted EU candidate status.