Spain is threatening to boycott the May 6-7 European Union summit in Zagreb because Kosovo will attend on an equal footing with other Western Balkan countries, Radio Free Europe reported on Wednesday.

Croatia, which has taken over the EU presidency for the first time, wants to confirm the European perspective for all the countries of the Western Balkans at the summit. Spain is one of five EU member states that do not recognize Kosovo and has been disputing Kosovo’s participation at European-level gatherings.  

RFE quoted what it said are reliable sources who told it that Spanish officials warned EU chair Croatia that Madrid would not be sending a delegation to Zagreb because Kosovo has been granted equal status with the other countries of the region. It added that several sources confirmed that other EU member states have been informed that Spain might not come to Zagreb.  

The Spanish government has not been willing to make an official statement because it has not received an official invitation yet. “It is too early to confirm the Prime Minister’s participation because we have not yet received an invitation from the Croatian presidency,” Spain’s EU embassy said.