Police fired tear gas to disperse protesters outside parliament on Sunday as tens of thousands of Greeks rallied in Athens to protest ahead of next week's parliamentary vote to ratify a name deal with Macedonia.
Central Athens turned into a sea of people holding blue and white Greek flags as thousands came from all over the country to rally against the accord to name the ex-Yugoslav state North Macedonia.
Many Greeks believe the name Macedonia implies a territorial claim over their country's own northern region of that name.
The accord, signed by the two governments, unblocks the ex-Yugoslav republic's desire to join NATO and the European Union once it is ratified by Greece's parliament.
Macedonia declared independence in 1991, avoiding the violence that accompanied much of the break-up of Yugoslavia. Prime Minister Zoran Zaev has sought to accelerate the country's bid to join the EU and NATO and to work on resolving the decades-old name dispute with Greece.Greece had agreed that until the name dispute is resolved, its northern neighbour, with a population of about 2 million, could be referred to internationally as "FYROM" - Former Yugoslav Republic of Macedonia. That is the name under which it was admitted to the United Nations in 1993.
The agreement with Skopje had strained relations with the right-wing Independent Greeks party, his coalition ally, which objected to the use of Macedonia in any agreed name.
United Nations diplomat Matthew Nimetz, who has mediated talks between the two countries, said he looked forward to Greece's ratification of the accord after FYROM delivered on related constitutional amendments.