Montenegrins are voting in a parliamentary election that could determine whether the small Balkan state continues on its Western course or turns back to its traditional ally Russia.
Some 530,000 registered voters will be voting for 17 lists, including a total of 34 parties. They are expected to elect 81 deputies.
Polling stations will close at 2000 hours and the first unofficial results will be released at 2100 hours.
The vote pits the long-ruling pro-Europe Democratic Party of Socialists, led by powerful Prime Minister Milo Djukanovic, against a cluster of pro-Russian and pro-Serbian opposition groups that staunchly oppose the country's NATO bid.
Pre-election polls have predicted the closest race since Montenegro gained independence from much larger Serbia a decade ago.
Montenegro had been a faithful ally of Russia. But after splitting with Serbia in a 2006 referendum, Montenegro took a strong turn toward Euro-Atlantic integration.
Analysts say the election campaign has focused less on the programs the parties have to offer and more on whether Djukanovic should stay or go.
The opposition has accused Djukanovic of corruption, nepotism, and economic mismanagement.
In 2003, Djukanovic was named a suspect in an Italian cigarette trafficking enquiry dating back to the 1990s. He denied the allegations and the Italian court dropped the case in 2009 because of his diplomatic immunity.
Djukanovic’s political ideology has undergone several transformations over the last two and a half decades in power. He first shed his communist, then nationalist, past to become a leading voice for EU and NATO integration.
Djukanovic has also accused the Kremlin of meddling in the election campaign by secretly financing the opposition parties in order to keep Montenegro from joining NATO.