Brussels - Spanish Prime Minister Mariano Rajoy will not attend an upcoming summit of EU and Western Balkans leaders over the participation of Kosovo, whose independence is not recognized by Spain, a senior EU official said on Tuesday.

It could fuel separatists

Spain's opposition to Kosovo's independence dates back to 2008, when the country decided not to recognize the breakaway former Serbian province over fears that it could fuel separatists in Spain's own Basque and Catalan regions.

The issue has become even more pronounced since a referendum last October over Catalonia's independence from Spain, which the country declared illegal. "It was very clear from the very beginning that due to the position of Spain on the status of Kosovo, Prime Minister Rajoy is not keen to participate in the summit," a senior EU official said, speaking on the condition of anonymity.

Which EU countries don't recognize Kosovo?

EU leaders and their counterparts from Western Balkan countries - Serbia, Bosnia and Herzegovina, Montenegro, Kosovo, Macedonia and Albania - are set to meet in Sofia on Thursday to discuss the region's European perspective.

Spain is not the only EU country that does not recognize Kosovo's independence - Greece, Cyprus, Slovakia and Romania also non-recognizers, however, their leaders will still attend the summit.

The EU has made it clear that while the meeting was meant to reaffirm the EU's commitment to integrating the region, it was not an accession summit. The bloc is expected to make commitments on increasing connectivity both within the region and to the EU.