"Government of the Republic of Macedonia" signs were removed from the country's main government building in the capital Skopje. Macedonian Prime Minister Zoran Zaev is scheduled to speak at ceremony Tuesday at the site, where organizers said the NATO flag is due to be raised.
Authorities well also preparing to replace signs at the country's border with Greece.
The small Balkan country will change its name to North Macedonia after reaching a landmark agreement over the summer with neighboring Greece, which has a neighboring province called Macedonia.
Macedonia is due to become a NATO member now that Greece's parliament approved a measure Friday that would allow the country to join the alliance. Greece had blocked Macedonia's accession to NATO for more than a decade.
Macedonia will now publish the deal with Greece in its government gazette so that the agreement can take effect.
The Greek and Macedonian governments want to implement the deal swiftly, faced with strong opposition from their domestic political opponents and skeptical public opinion on both sides of the border. More than two-thirds of Greeks opposed the agreement, according to several recent opinion polls, while a referendum on the deal in Macedonia last year saw more than 60 percent stay away from the vote.
"The government building has been left with no official sign - it's an embarrassing action by the prime minister," said Naum Stoilkovski, a spokesman for Macedonia's conservative opposition party VMRO_DPMNE.
"The Republic of Macedonia has been dishonored and disfigured."
With a struggling $11 billion economy, Macedonia has craved stability since gaining independence from Yugoslavia in 1991, but its integration with other European countries was held back by its dispute with Greece and international tension about Macedonia's future NATO membership, which is strongly opposed by Russia.
Boris Grdanoski in Gevgelija contributed to this report.
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