European Union leaders will be able to restate their guarantee of future membership to six Balkan countries on Wednesday at a summit, after EU ambassadors agreed a text on Monday, a senior EU official said.

After weeks of disagreement over the wording of a summit declaration for Wednesday's gathering of EU and Balkan leaders in Slovenia, envoys from the EU's 27 states reached a deal to "reconfirm... their unequivocal support for a European perspective," the official said.

The impasse during September over the declaration was seen as a reflection of the lack of enthusiasm in EU capitals for bringing Serbia, Kosovo, Bosnia-Herzegovina, Montenegro, Albania and North Macedonia into the bloc.