Scenes of desperate migrants being teargassed at the border between Greece and the Former Yugoslav Republic of Macedonia are straining an already testy relationship between the two neighbors, as Skopje also grapples with a political crisis that has seen protesters ransack the president's office.
With thousands of people camped out on the Greek side of the border in squalid conditions, the two countries have traded increasingly undiplomatic protests, with Greece accusing non-EU FYROM of unacceptable tactics in its use of tear gas -- and rubber bullets according to doctors on the scene -- and Macedonia accusing Greece of inaction.
The violent scenes unfolded at the flashpoint Idomeni border crossing last week as hundreds of migrants tried to break through a fence following a rumor the crossing was about to be re-opened.
Skopje last month closed its border with EU encouragement, after a succession of EU states voiced alarm at the mounting flow of Syrians, Iraqis, Afghans and other people fleeing war and poverty.
Greek Prime Minister Alexis Tsipras said FYROM had "shamed" Europe by its actions while President Prokopis Pavlopoulos went a step further, arguing such "incomprehensible" behavior showed FYROM had "no place" in the EU or NATO.
FYROM President Gjorge Ivanov shot back that it was Greece's job to prevent migrant incursions on its soil, a task he said Athens has repeatedly failed to live up to.
The war of words is just the latest in a long and troubled history between the two neighbors.
Greece and FYROM have been at loggerheads over the right to the name Macedonia since the early 1990s.
When the former Yugoslav republic proclaimed independence in 1991, it took the name Republic of Macedonia, the same name as a northern Greek province.
Athens worries it could imply a claim on its territory, and the Greeks also accuse Skopje of trying to usurp the heritage of the ancient Macedonians and stake a claim to Alexander the Great, one of antiquity's greatest warriors.
Ioannis Armakolas, an assistant professor of comparative politics at the University of Macedonia in northern Greece, says EU aspirant FYROM will have been happy with its handling of the border situation.
"For (Skopje) specifically, the handling of the crisis was a success and an upgrade of its role, because it became indispensable for the resolution of this crucial European security problem," Armakolas said.
But with Britain's Brexit vote looming, the ongoing refugee crisis and economic malaise leaving weaker EU members with record unemployment and austerity, Armakolas argues that it is unlikely to translate into tangible advances for FYROM's EU membership hopes.
"The EU is in such a deep crisis that it's totally unrealistic to expect any new noteworthy attempts to promote enlargement issues," he said.
FYROM has been a candidate for EU membership since 2005 but accession talks have yet to open and a prolonged political crisis has not improved its chances.
Another source of discord between the two neighbours is FYROM's NATO ambitions.
FYROM's application to join NATO was blocked in 2008 by Greece as part of the name row.
The country's current political crisis would be "a cheap excuse" for Greece to continue blocking both FYROM's EU and NATO aspirations, FYROM's Foreign Minister Nikola Poposki told AFP.
Protesters rampaged through President Ivanov's office on Wednesday and set fire to the furniture after he blocked legal proceedings against top politicians involved in a wire-tapping scandal.
Twelve people were arrested and a journalist was injured in clashes with riot police.
For all the difficulties, however, Poposki still believes FYROM will advance its cause by its handling of the migrant crisis.
"We have a pretty positive track record in the last period in cooperating with Greece... the migration crisis can be an opportunity to strengthen these ties," he said.
"It has always been (difficult) in the Balkans. But these difficult times are an opportunity for us to strengthen this cooperation."
Aris Vlachos, a business consultant who headed FYROM's international council of investors for a decade, notes that Greek entrepreneurs have pumped around a billion euros (dollars) into the country's economy in the past two decades, creating some 20,000 jobs.
"There have been better times," he concedes. "(But) Greek businesses there are a factor of stability... relations with local businessmen are based on years of cooperation and we try not to put politics in the way," says Vlachos, who has lived in the country since 1995.