Allowed to fester for more than a decade, an emboldened Serb nationalism seeks to exert its power in a region that has not fully recovered from the words of the 1990s.
Against the backdrop of the recently erected statue of Stefan Nemanja in Belgrade, a tenth-century medieval monk and historical ruler of Serbia, the country marked its new national holiday on September 15: Day of Serbian Unity, Freedom and National Flag.
The country's president Alexander Vucic, the Bosnian Serb leader Milorad Dodik and Serbian Orthodox Church Patriarch Porfirije each went on stage to deliver their vision of a re-emerging Serb world in the Balkans. Blood, faith and unity were the rallying cries.
In the lead up to the celebrations, the country's foreign minister, Nikola Selakovic, lamented that not enough had been done to "build and respect the cult of the flag."
Amongst politicians in Belgrade, the disintegration of Yugoslavia in the 1990s is seen as a tragedy and Serbia is the victim of a great injustice made to feel ashamed of the country's past and its flag.
The grievance goes along the lines that its wars in the 1990s against Bosnians and Albanians, two mainly Muslim communities, culminating in widespread ethnic cleansing - was an exaggeration.
In the minds of Serbian politicians, leaders convicted in international courts for their crimes in the 90s only heaped further humiliation and reflected a plot by an international cabal seeking to destroy the Serb nation.
Source of instability
When Kosovo decided to introduce a five euro ($6) fee for cars entering from Serbia last week, the country's strongman leader Vucic saw an opportunity to flex some muscle and restore some lost national pride.
The Kosovan government says that their decision is an act of reciprocity, reflecting Serbia's ongoing barriers that Albanians have in crossing the border.
Belgrade’s reaction to Pristina’s move was to have its military strut along the border menacingly. The recent military moves by Serbia on Kosovo's northern border, shows that Belgrade is anything but a force for stability in the region, said a Kosovan based security analyst speaking to TRT World on condition of anonymity.
"The investments made to date by the international community in treating Serbia with great preference are turning into a fallacy," they said.
European powers and even the US — which bombed Serbia only in 1999 in a bid to halt the ethnic cleansing in Kosovo — have in recent years sought to appease and befriend Belgrade as a means of peeling it away from Russian influence.
That is increasingly looking like wishful thinking. The use of Russian helicopters near the Kosovo border as a show of strength and even more recently, Belgrade announcing that it will host a joint military exercise with Moscow is a "message to the West," said the security analyst.
The Russian Ambassador to Belgrade, Alexander Botsan-Kharchenko, accompanied by the Serbian Chief of Staff Milan Mojsilovic, even went close to the border with Kosovo over the weekend to inspect military personnel, a move that has only heightened tensions.
"The situation is certainly of high risk that should not be undermined," added the security analyst going on to warn that without diplomacy, events on the ground have the "potential to escalate into a sporadic armed confrontation with spillover effect also in other parts, including in Presheva Valley," an Albanian region in southern Serbia.
With presidential and parliamentary elections in Serbia fast approaching, Vucic has to be an "ethnic hardliner", a Belgrade based security analyst told TRT World on the condition of anonymity to speak freely.
"There is no way Vucic is going to war with NATO, again! So this is just a power play for the domestic audience but possibly terrible for the Serbs in northern Kosovo," said the security source.
For all the talk of pan-Serbian brotherhood, Vucic has adeptly sought to instrumentalise the Serbian minority in Kosovo - even if it means keeping them economically and politically isolated.
Vucic seeking to become the saviour of Serbs in the region is "unfortunately the only game in town, and it works every time," added the security source, pointing out that Belgrade's flag day is symbolic of Belgrade's growing confidence to project its nationalism more confidently across the region’s Serbian population in service of domestic politics.
The new government in Pristina, led by the recently elected Prime Minister Albin Kurti from centre-left Levizja Vetevendosje (LVV) — Kosovo's Self-determination party has urged Belgrade to sit down and negotiate.
A source close to the LVV party told TRT World that "Serbian escalation is primarily meant for domestic political consumption, but Vucic also hopes it might give him the upper hand in negotiations."
Even as Serbia has amassed troops on Kosovo's borders and fighter jets fly close to the border crossing between the two countries, European Union leaders have been loath to take a stand.
"The continuous appeasement of Serbia is dangerous because it emboldens Vucic in his attempts to further destabilise the region," said the LVV source adding that "it's disappointing to see even certain allies adopting the "both sides should show restraint" approach."
Dr Sidita Kushi, an Assistant Professor of Political Science at Bridgewater State University, warns that Belgrade's recent "acts of aggression" should be understood as part of a wider pattern of behaviour driven by domestic and international factors.
"Internationally, such militaristic responses provide political fodder for Serbia's revisionist history narrative, in which it portrays itself as the rightfully aggrieved party," says Kushi speaking to TRT World.
Serbian sabre-rattling also makes "political concessions from the EU more likely," which often prioritises stability in the region over the rule of law or democracy, says Kushi.
If Vucic has learnt anything in recent years is that he can "escalate a situation while also receiving praise and concessions for eventually ‘de-escalating it’, as per EU appeals," added Kushi.
When TRT World contacted the Serbian Ministry of Foreign Affairs (MFA), they said that the military is not "conducting any military manoeuvres at the moment." However, online footage and regional observers have contradicted such claims.
The MFA went on to call for a "return to status quo ante" wherein Serbia places restrictions on Kosovo's vehicles and people, but the same rules are not applied in return.
Such statements ultimately seek to "portray Kosovo as the aggressor, with the intention of isolating Kosovo from international support," says Kushi.
In the long run, the EU's and US's "lukewarm" backing of Kosovo in the face of growing "nationalism and authoritarianism" in Belgrade will "embolden Serbia towards more aggression and perhaps a direct military invasion," warns Kushi.
For Kurti's government, with EU countries like France and Germany keen to normalise relations with Russia and with both actors currently in an election season, Kosovo seeking to establish its sovereignty is low on their priority list.
Further afield the Joe Biden administration is tied up with domestic politics and China and is unlikely to see the Balkans as an area of priority. While the damaging presidency of the Trump administration, whose interference in Kosovo's politics ended up toppling the previous government, is over, Biden's benign neglect may have no less severe consequences.
"Unfortunately, as long as the West's ‘both sides’ framings continue, they will only serve to strongarm the weaker actor, Kosovo, and to embolden and justify the past violence and present aggressive policies of the stronger actor, Vucic's Serbia,” added Kushi.