Up to 100,000 Greeks converged on Athens on Sunday to demonstrate against a landmark deal that will see Macedonia, the country’s northern neighbour, change its name.

With MPs poised to ratify the deal on Thursday, an otherwise peaceful demonstration quickly descended into violence as rock-and-stick wielding protestors tired to storm the parliament and riot police responded firing rounds of teargas.

The clashes, which further polarised a nation fixated by the name dispute for decades, left dozens injured including 25 police and two photojournalists, authorities said.

Under the accord, reached between Athens and Skopje last June, the tiny Balkan state will be renamed North Macedonia, resolving a row that began with the dissolution of Yugoslavia almost 30 years ago.

Protesters clash with police in front of the Greek parliament in Athens. Photograph: Louisa Gouliamaki/AFP/Getty Images

Greece’s leftist prime minister Alexis Tsipras, who blamed Sunday’s clashes on far-right extremists, claims the agreement will “cement relations of friendship” with a nation whose name is widely feared to connote territorial aspirations against the Greek region of Macedonia.

But for the thousands of protesters who had travelled by bus, plane and ferry to chant “Macedonia is Greek” in front of the parliament building in Syntagma Square yesterday, the compromise doesn’t go far enough

“Macedonia is one and it is Greek,” said Andreas Androutsos, a young engineer, deploying a refrain echoed by many attending the demonstration. “What the government is doing is fascistic. It is trying to pass an agreement that so many of us are against. Macedonia belongs to the Greek people, it doesn’t belong to any political party.”

Under the accord, known as the Prespes agreement, Greek MPs are required to ratify the deal after parliamentarians in Skopje endorsed earlier this month. Once passed, the rechristened Balkan country can begin accession talks with Nato and the EU – alliances Greece has blocked because of the dispute.

Organisers had hoped to attract as many as 600,000 protesters to pressure the government into holding a referendum on the deal but turnout fell well short of that, according to police. Of the 3,000 buses lined up to travel to the capital, mostly from the country’s north, only 326 were recorded clocking in at tolls on national highways.

The parliament is to vote this coming week on whether to ratify the agreement that will rename its northern neighbour North Macedonia. Photograph: Miloš Bičanski/Getty Images

Yet hostility to the accord remains visceral and deep. In a nation humiliated by the depredations of years of economic crisis, successive surveys show around 70% of Greeks are opposed to the agreement.



“Millions of Greeks are, and will continue to be, against the Prespes agreement,” tweeted the country’s conservative former prime minister Antonis Samaras, a nationalist whose career was first fermented by the dispute. “Whatever provocation they come up with, however much teargas they spray, people will remain unbowed for Macedonia.”



Among the most trenchant criticism is the belief that Slavic Macedonians are bent on appropriating Greek history, not least the ancient warrior king Alexander the Great.

Demonstrators, who included diaspora Greeks who had flown in from as far away as the United States and monks from the monastic community of Mount Athos, were united in vehemence on Sunday that the accord – and its acceptance of a “Macedonian nationality and language - not only amounted to cultural theft but could buttress future irredentist claims.

“All the findings show that Alexander was a Greek. He spoke Greek, he thought in Greek, there was nothing Slavic about him,” said Chrysanthi Papageorgiou, a woman who had come in from Athens’s poorer western suburbs with her husband Yannis for the protest. “We are not against our neighbours but we are going to defend our rights. We are not going to submit or surrender to them.”



Tsipras claims the pact protects Greece’s cultural heritage by drawing a “clear distinction” between the eponymous Greek region, its ancient civilisation and the neighbouring country.



With his social democrat counterpart Zoran Zaev, the Greek leader has won international praise for the determination both have displayed ending a dispute whose settlement is regarded as a rare feel-good story for Europe.



In capitals across the EU there is a consensus that the accord will shore up stability in the Balkans at a time of increased Russian interference across the volatile region. Both prime ministers have been nominated for the Nobel peace prize this year in recognition of the political courage they have been credited with exhibiting.



But the scale of the opposition shows that winning over hearts and minds remains an uphill struggle.



Tsipras, who narrowly won a vote of confidence last week, controls 145 seats. But with the help of deputies who have defected from his coalition’s erstwhile junior partner, the Independent Greeks party, and centrists, is minority government is expected to prevail].



The centre-right main opposition party, New Democracy, which has demanded an inquiry into the brute force used to quell Sunday’s unrest, has been staunchly critical of the accord.

A man holds a Greek flag in a cloud of teargas. Photograph: Miloš Bičanski/Getty Images

But strength will lie in numbers. “If it is to have legitimacy and no one is to question the deal afterwards, it is important that it is supported by as many as possible,” said Stelios Kouloglou who represents the ruling Syriza party in the European parliament.



MPs, particularly in northern Greece, have received death threats ahead of the parliamentary vote.



Yet the prospect of holding a public plebiscite on such a divisive issue has also elicited dread.



“It will be very polarising,” said Eleftheria Giammaki, a schoolteacher standing before a banner proclaiming “resistance to nationalism” at a counter-rally staged by anti-establishment leftists down the road.



“Nationalism is a great curse. We need to move beyond this issue as quickly as possible.”