Montenegro defied Russia on Sunday by electing a pro-Nato political veteran who hopes to lead the small Balkan state into the European Union.
On Sunday night, officials announced that Milo Djukanovic, who has dominated politics in the former Yugoslav republic for nearly 25 years, had secured victory.
Milos Nikolic, a spokesman for the ruling Democratic Party of Socialists, said: "Milo Djukanovic is the new president of Montenegro... this is a great victory, a historic victory."
The result is likely to rattle pro-Russian groups who bitterly opposed Montenegro joining the Western military alliance in 2017.
It would also allow Mr Djukanovic, who favours deeper European integration, to push for Montenegro to become an EU member, which experts say could happen as soon as 2025.
His main rival was Mladen Bojanic, an economist who has the support of most opposition parties, including pro-Russian factions, and is expected to secure around a third of the vote.
Mr Djukanovic also ran against centre-left lawyer Draginja Vuksanovic, who was the country's first ever female presidential candidate in a staunchly conservative and male-dominated society.
On Sunday, Mr Bojanic said he would "put an end to the reign of an autocrat who wants to turn Montenegro into a dictatorship".
Earlier in the campaign he also accused Mr Djukanovic of being "the creator of the instability and chaos that we witness in the streets of Montenegro," referring to a rise in organised crime, including people trafficking.
"I agree with Djukanovic that the state is stronger than mafia. But the problem is that I do not know which side he is on," he added.
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However, Mr Djukanovic has claimed that the opposition wants to turn the country into a "Russian province" and threaten Montenegro's multicultural way of life.
Mr Djukanovic was prime minister during a tense October 2016 parliamentary election when authorities said they thwarted a pro-Russian coup attempt designed to prevent the country from joining Nato.
Two Russian citizens are being tried in absentia for the plot, which prosecutors said included a plan to assassinate Mr Djukanovic. The Kremlin has denied any involvement.
Map of Nato membership in Europe
In 2006, Mr Djukanovic led Montenegro to independence from Serbia, which also hopes to became an EU member within the next seven years.
Speaking to local media after casting his vote, Zdravko Ivanovic, 84, praised Mr Djukanovic's leadership, describing him as "the best statesman and prime minister, the best and finest Montenegrin giant."
But Radmila Cagorovic, a voter in her late 50s, disagreed - "we have waited so long for a change. I hope it will happen today," she said.