Greeks and Macedonians expressed scepticism on Wednesday over a proposed compromise deal to end a nearly three-decade name row between their countries which has blocked Skopje's bid to join the EU and NATO.
The leaders of the neighbouring countries hailed a "historic" agreement on Tuesday to rename the tiny Balkan nation the Republic of North Macedonia, after months of intensive talks.
However, Greece's conservative opposition quickly branded the deal a "national retreat", while Macedonia's nationalist President Gjorge Ivanov stormed out of a meeting with the prime minister and foreign minister in protest.
Greece has long objected to its northern neighbour being called Macedonia because it has its own northern province of the same name, which in ancient times was the cradle of Alexander the Great's empire -- a source of intense pride to modern day Greeks.
"President Ivanov interrupted the meeting and left refusing to talk about the benefits of this historic agreement on the Macedonian future," Macedonia's government said.
The meeting lasted less than three minutes, officials said.
"I will neither support nor sign this harmful text," Ivanov said later Tuesday in an address to the nation.
The deal was reached "without a broad national consensus and was not transparent," he argued.
The agreement still needs to be approved by Macedonia's parliament and pass a referendum there, as well as being ratified by the Greek parliament.
Ivanov can veto the parliament's decision only once and has no power to veto a referendum.
Macedonia's nationalist VMRO-DPMNE party condemned the deal as "an absolute defeat of the Macedonian diplomacy in every possible way."
There was also resistance to the deal on the streets of Skopje.
"We went too far, we allowed too much," said Suzana Turundzieva, a 46-year-old retail worker.
Athens, however, defended the name agreement.
"I believe that yesterday we made a very decisive step for the stability of the broader Balkan region," Greek government spokesman Dimitris Tzanakopoulos told state TV ERT.
Tuesday's breakthrough was quickly welcomed by the United Nations, NATO and the EU with European Council president Donald Tusk tweeting: "Thanks to you the impossible is becoming possible."
On Wednesday he issued a joint statement with NATO chief Jens Stoltenberg, voicing the hope that "this unique opportunity to relaunch the wider Western Balkan region's European and Euro-Atlantic integration will not be wasted".
- 'A trick' -
However, the two governments face significant hurdles at home over the deal, with the countries' main opposition parties refusing to support it.
Street protests have also been held in both nations against any compromise.
New demonstrations against the deal were announced to be held in Athens on Friday and Saturday in front of the parliament.
Much of the criticism in Greece has focused on the government's acceptance that the neighbouring country's language and ethnicity will be called "Macedonian".
"The acceptance of the Macedonian language and nationality is an unacceptable national retreat," said main opposition leader Kyriakos Mitsotakis.
Others argue that with Turkey proving an increasingly volatile neighbour, it made sense to close the long-running diplomatic dispute.
- 'Great diplomatic victory' -
Macedonian Prime Minister Zoran Zaev welcomed the deal on Tuesday, saying "we have a historic solution after two and a half decades. Our agreement includes Republic of North Macedonia for overall use".
Greek Prime Minister Alexis Tsipras declared it "a great diplomatic victory and a great historic opportunity" for the region.
Critics say Tsipras, who has a slim majority in parliament, lacks legitimacy to enforce the deal because his nationalist coalition partner has refused to support it.
But he is expected to be able to get the deal approved thanks to the backing of a number of smaller Greek opposition parties.
Observers have warned there is a real risk that the world will simply continue referring to the country as "Macedonia", which would constitute a major failure for Greece.
Questions were also raised about what Greece could do if a hardline government comes to power in Skopje and refuses to carry through the promised reforms -- including an overhaul of vehicle license plates, passports and administrative documents -- as the procedure is likely to take years.
"This looks like a preliminary deal... so we should restrain our expectations," Greek analyst Constantinos Filis told SKAI TV.
Skopje hopes to secure a date to begin accession talks at an EU summit in late June, and an invitation to join NATO in mid-July.