More than 1,000 Macedonians protested on Saturday evening against the change of the name of the former Yugoslav Republic which was agreed with neighboring Greece to end a decades-long dispute.

Last week, the foreign ministers of Greece and Macedonia signed an accord to rename the tiny ex-Yugoslav republic the “Republic of North Macedonia.”

The agreement, which unlocked Macedonia’s path to possible European Union and NATO membership, triggered protests by nationalists.

The protest on Saturday evening organized by Macedonia’s biggest opposition party, VMRO-DPMNE, was peaceful. Protesters held banners reading “We don’t want to give up the name” and waved Macedonian flags as they demanded annulment of the agreement with Greece.

Macedonia, which declared its independence in 1991, avoided the wars that battered some other ex-Yugoslav republics. But Greece refused to accept the country’s name, saying it implied territorial claims on the Greek province of Macedonia and amounted to an appropriation of its ancient civilization. Greece blocked Macedonia’s efforts to join the European Union and NATO.

Macedonia has to amend its constitution to conform with the provisions of the deal. A referendum is also expected in Macedonia in the autumn.

Macedonian President Gjorge Ivanov also opposes the accord. He refused to sign the agreement even though it was ratified by parliament on Wednesday.