The EU last year suspended pre-entry talks with Belgrade over its failure to arrest UN war crimes fugitive Ratko Mladic and other suspects sought by the war crimes tribunal.
On Thursday, Zdravko Tolimir, a former Bosnian Serb general and senior aide to Mladic charged with genocide and crimes against humanity, was arrested on the Bosnia-Serbia border.
Tolimir will make his first appearance before the International Criminal Court for the Former Yugoslavia on Monday.Co-operation
Rehn said a precise date for new talks would be set after Carla Del Ponte, chief UN war crimes prosecutor, visits Belgrade on Monday to review Serbia's co-operation.
|"There is plenty of evidence that Serbia is taking concrete and effective action towards full |
EU Enlargement Commissioner
He added that in his view "there is plenty of evidence that Serbia is taking concrete and effective action towards full co-operation".
Friday's meeting saw little sign of movement on the other contentious issue before entry talks, the future of the breakaway province of Kosovo.
Martti Ahtisaari, UN envoy, has recommended that the province be granted internationally supervised independence.
The proposal has been welcomed by the region's ethnic Albanian majority, who comprise 90 per cent of the two million population, but vehemently rejected by its Serb minority, Serbia, and its ally Russia.
Merkel said she made clear on the EU's behalf that a UN resolution "on the basis of the Ahtisaari plan" should be adopted.
Tadic responded that the Ahtisaari plan was "absolutely unacceptable, because it contributes to Kosovo becoming independent".
"Something that is completely unacceptable for one side cannot be declared a compromise," he added. "In a compromise there should be no losers."