SKOPJE, Macedonia (AP) — The president of Macedonia has urged voters to abstain from a referendum on changing the country's name to clear its path toward NATO and European Union membership.

President Gjorge Ivanov said during the last hours of campaigning for Sunday's referendum that changing the nation's name to North Macedonia would be a "flagrant violation of sovereignty." He spoke Thursday at the U.N. General Assembly in New York.

Voter turnout is critical, as the referendum will be valid only if more than 50 percent of voters participate. Polls indicate a "yes" vote would prevail, but turnout might fall short.

Ivanov, a conservative, opposes the deal on which left-wing Prime Minister Zoran Zaev has staked his political future.

Police say a student protest against the name change planned for later Thursday was cancelled.