BELGRADE, Serbia — Serbia’s strongman leader, Aleksandar Vucic, is fed up with being reviled as a “little Putin” intent on aggression against his country’s fragile neighbors in the Balkans.

For starters, Mr. Vucic noted wryly in an interview in the library of the presidential palace this month, “I am almost two meters tall.” That makes him about 6-foot-5. (Vladimir V. Putin is an estimated 5-foot-7 at most, though the Russian president’s exact height, a sensitive topic for the Kremlin, is a secret.)

Behind Mr. Vucic’s levity over physical stature, however, lurks a

serious question that torments the Balkans and preoccupies Western diplomats. 

Is Russia, mired in a brutal war in Ukraine, using Serbia to stir division in Europe and provoke renewed conflict in the former Yugoslavia to distract NATO from the battle raging to the east?

Those fears flared last week when an esoteric dispute over license plates between Serbia, which is bound to Russia by history, religion and deep hostility toward NATO, and the formerly Serbian province of Kosovo led to unruly protests, roadblocks and gunfire — setting off alarm bells in the Atlantic alliance.

The unrest in Kosovo, and strains in nearby Bosnia and Herzegovina caused by Milorad Dodik, the belligerent, Moscow-backed leader of the ethnic Serb enclave there, and by hard-line Croat nationalists have led to warnings that Russia is trying to stoke tensions, stilled but never really resolved, from the Balkan wars of the 1990s.

“Russia calculates that the more time the West spends sweating in the Balkans, the less time it will spend sweating in Russia’s backyard,” said Vuk Vuksanovic, a researcher at the Belgrade Center for Security Policy.

“But there are limits on what Russia can do,” Mr. Vuksanovic added. “It needs local elites and these don’t want to be sacrificed for Russian interests.”

America’s ambassador to Serbia, Christopher R. Hill, a veteran diplomatic troubleshooter whose recent appointment signaled Washington’s heightened anxiety over the Balkans, said that Russia, offering only “economic blackmail” and “chaos throughout the region,” had found few takers.

“Despite Russia’s influence on Serbia’s energy sector and despite its pervasive disinformation efforts here, Serbs have decided that their future is with Europe and the West,” Mr. Hill said.