Serbia’s Leader Tightens Grip on Power in General Election, Early Results Show

President Aleksandar Vucic, Serbia’s strongman leader and Russia’s closest ally in Europe, tightened his decade-long grip on power on Sunday with what preliminary results indicated was a big win for his governing party in a snap general election.

Like all previous elections in the deeply polarized Balkan nation, Sunday’s poll was marred by reports of voting irregularities and complaints that Mr. Vucic’s stranglehold on much of the Serbian media and on a large state sector employing hundreds of thousands of voters had again given his party an unfair advantage.

The president, speaking late Sunday at his party’s headquarters in Belgrade, the Serbian capital, declared himself “extremely happy” at what he described as “absolute victory.”

Partial official results and an exit poll by the polling organization IPSOS and the Center for Free Elections, an independent Serbian monitoring group, pointed to a large majority in Parliament for Mr. Vucic’s nationalist governing party, the Serbian Progressive Party, and its allies.

Mr. Vucic’s party, which for the election rebranded itself under the name Serbia Must Not Stop, appears to have won twice as many votes overall as its main rival, an alliance of diverse opposition groups called Serbia Against Violence. Seats in Parliament are apportioned under a complicated proportional system and the exact composition of the legislature will not be clear for several days.

The opposition had hoped to ride a wave of public revulsion at back-to-back mass shootings in May but, shut out by national television channels and pilloried by incendiary pro-government tabloids, was unable to convert the energy of huge anti-violence street protests over the summer into a successful election challenge.

For a time over the summer, it looked as if Mr. Vucic, abandoned by some of his allies and under mounting pressure from the street, might be losing his grip. But his party again proved itself a formidable political machine capable of mobilizing voters, including some, according to election monitors, who had no right to vote in the places they cast their ballots.

The Center for Research, Transparency and Accountability, an opposition-inclined pro-democracy organization, reported “a large number of cases” of voters being bused into Belgrade from other parts of Serbia and from neighboring Kosovo and Bosnia, which have large populations of ethnic Serbs who tend to tilt strongly nationalist.

Opposition parties appeared to have performed better in municipal elections in Belgrade, but it was unclear whether the city, Serbia’s biggest and an important power center in its own right, would pass under the control of Mr. Vucic’s mostly pro-Western liberal and centrist opponents.

Mr. Vucic declared victory in Belgrade, but the opposition leader Marinika Tepic vowed to contest results there, saying “we will use all democratic means to defend the will of all citizens of Serbia.” Control of the capital is seen as a particularly important prize, as it was a contested election in the city in 1996 that galvanized opposition to Slobodan Milosevic, Serbia’s leader at the time, and helped set in motion forces that led to his downfall in 2000.

Serbia, the most populous country that emerged from the ruins of former Yugoslavia in the 1990s after wars unleashed by Mr. Milosevic, has a population of less than seven million, but it has commanded the attention of the United States and the European Union as the pivot around which of many of the volatile region’s problems, including regular eruptions of violence in mainly ethnic Serb areas of Kosovo, revolve.

But Mr. Vucic has so far frustrated hopes in Washington and Brussels that Serbia would move toward recognizing the de facto, if not legal, independence of Kosovo, a formerly Serbian territory that declared itself an independent state in 2008. While professing a desire to join the West, Mr. Vucic has resisted pressure to tilt away from Russia, Serbia’s traditional ally and protector, and accelerate its long-stalled and often halfhearted efforts to join the European Union.

Serbia declined to join Western sanctions against Russia over the war in Ukraine, and it has a sometimes violent ultranationalist community committed to the 1990s cause of a “Greater Serbia,” a Serbian version of the Kremlin’s irredentist claims to Ukraine and other formerly Soviet territories that Moscow views as part of the “Russian world.”

The result in Sunday’s election could, in theory, give Mr. Vucic more leeway to forge a peace agreement with Kosovo and break with Russia, especially as the far-right nationalist party ofVojislav Seselj, a convicted war criminal, failed to win any seats.

Mr. Vucic, a wartime protégé of Mr. Seslj, called early elections in a bid to reassert his authority, badly dented by the anti-violence protests. Though facing no serious challenge from foes or estranged former allies, he has shown little inclination to give up his longstanding tactic of maneuvering between East and West and avoiding steps on Kosovo that would risk a backlash from hard-line nationalists.

The results dashed the hopes of Mr. Vucic’s opponents for a return to power after more than a decade on the sidelines. In a rare show of unity, Serbia’s usually fragmented and feuding opposition groups mostly banded together to present a united front. But there were still nearly 20 different groupings on the ballot.

Unable to compete with Mr. Vucic’s deeply embedded nationwide support network and his sycophantic media machine, the opposition struggled to convert public anger over gun violence and links between the government and organized crime into the political momentum it needed to break an increasingly authoritarian system.

Alisa Dogramadzieva contributed reporting.