Spanish officials have warned the hosts of the upcoming summit that they will not attend a meeting where Kosovo has equal participation with other Western Balkan countries.
But according to sources, diplomats from other European Union countries have already been told that Spain may bypass the Zagreb Summit.
This Summit between EU and Western Balkans representatives will be held on May 6-7.
Spain does not recognize Kosovo's independence.
The government in Madrid has challenged Kosovo's equal participation in all European-level rallies.
It has previously boycotted similar meetings.
In 2018 in Sofia, when the Western Balkans Summit was held for the first time in 15 years, official Madrid did not attend for the same reasons.
At an informal meeting of EU and regional foreign ministers held in Helsinki last August, then-Spanish Foreign Minister Josep Borrell left the room due to the presence of Kosovo's minister.
At the time, he had not been nominated for the post of EU foreign policy chief.
Asked by Balkan Radio Free Europe Service about possible problems in organizing the summit due to Kosovo's equal participation, Croatian Parliament Speaker Gordan Jandrokovic said it was not easy to match the interests of all the EU member states.
"When there are different interests, then the negotiations take longer," said Jandrokovic, who confirmed that Croatian Prime Minister Andrej Pllenkovic is in touch with all European leaders about organizing the summit.
Jandrokovic also said that the Croatian government would do everything possible to give the Western Balkan countries a clear European perspective.
“Not all EU countries have such an attitude and enthusiasm. We will speak in the best interest of our neighbors,” he said.
According to Free Europe Radio sources, officials in Zagreb are convinced that a formula will be found by May that will allow all Summit guests to attend it.