Greeks gathered outside parliament in Athens on Sunday to protest against the use of the term Macedonia in any settlement the government pursues with the ex-Yugoslav Republic to end a decades-old name dispute.
Efforts by the two countries to settle the dispute, which has blocked Macedonia's aspirations to join Nato and the European Union, have been inconclusive since the small Balkan state broke away from Yugoslavia in 1991.
Greece objects to Macedonia's name because it has its own territory called Macedonia, and argues that its small northern neighbour's use of the name, along with contentious articles in its constitution, imply territorial claims over Greek land.
Due to Greece's objections, Macedonia was admitted to the United Nations with the provisional name "The Former Yugoslav Republic of Macedonia" in 1993, which remains its official title in international organisations.
Organisers expect a big turnout for Sunday's rally.
"Macedonia means Greece" read a big banner on Syntagma square, which has been the main scene of protests against austerity since the debt crisis began in 2010. Protesters waved Greek flags and held banners reading "Hands off Macedonia!"
Among key speakers is world-renowned Greek composer Mikis Theodorakis. Hours before the rally, unknown assailants threw red paint outside the home of the 93-year old leftist artist, a symbol of resistance against the 1967-1974 military junta, and sprayed slogans on the walls against his involvement.
About 300,000 people turned out at a demonstration on January 21 in Thessaloniki, capital of Greece's Macedonia region.
The case arouses strong emotions among Greeks who consider Macedonia, the ancient kingdom ruled by Alexander the Great, to be an integral part of their homeland and heritage.
The left-led government has proposed a compound name, with a geographical qualifier, which would be the only name that could be used for the country.
A poll published in the conservative Kathimerini newspaper showed that about 70% of Greeks oppose the use of "Macedonia" in any solution.
The issue has triggered domestic upheaval in the past; in 1992, the then conservative government was riddled by dissent and defections. Today, the same political party has criticised the present administration for its negotiation tactics.
Foreign Minister Nikos Kotzias said last week that Greece is preparing proposals which would be the basis of negotiations for a settlement with its neighbouring country.