Montenegrin Prime Minister Milo Djukanovic and leader of ruling Democratic Party of Socialists celebrates after parliamentary elections in Podgorica on October 17, 2016
Podgorica (Montenegro) (AFP) - Montenegro's premier Milo Djukanovic appeared likely to extend his long term in office Monday after coming first in elections marred by the arrest of 20 Serbs accused of planning attacks.
With virtually all votes counted, the veteran leader's Democratic Party of Socialists (DPS) had won more than 40 percent -- more than double that of the main opposition Democratic Front.
However, Djukanovic fell short of an overall majority meaning he will have to begin long coalition negotiations, sparking fears of political instability in the ex-Yugoslav country of 620,000 people.
Two other parties, Kljuc (Key) and the Democrats of Montenegro, won ten percent each, according to the results of a vote that was seen as a choice between closer ties with the West or with long-time ally Russia.
Tensions were already running high over Djukanovic's plans to forge closer ties with the EU and NATO and were further inflamed after the dramatic arrest of the 20 Serbs.
Six of the suspects have since been released, prosecutors said Monday, adding they are trying to "identify other people shown to belong to this group in order to arrest them."
Authorities said the Serbs -- with retired police chief Bratislav Dikic allegedly at the helm -- plotted to seize the prime minister and parliament and proclaim victory for the opposition.
"We suspect that this criminal group was aiming to arrest the prime minister of Montenegro," the prosecutor's office said.
"The plan was to attack citizens gathered outside parliament, as well as police, during the announcement of the results, and then take control of parliament and proclaim victory for the opposition," it said.
- 'Not linked to Serbia' -
One of the six founding republics of the former Yugoslavia, Montenegro joined a loose union with neighbouring Serbia after the Yugoslav breakup.
This ended in 2006, when the country narrowly voted in favour of independence, and relations with Serbia have been fraught ever since.
The pro-Russian opposition branded the arrests as propaganda, while Serbian Prime Minister Aleksandar Vucic said he "personally did not believe" in the plot.
"I would like to see and hear serious information that he (Dikic) was planning terrorist acts," Vucic said, according to the Tanjug news agency.
Vucic had previously questioned the timing of the arrests.
"I find it curious that this is happening today, and that's all I'll say... As for the rest, it would be better for me to bite my tongue."
Montenegro's deputy prime minister Dusko Markovic earlier defended the arrests, saying they were "performed in a professional and legal way."
He added the suspects are "not linked with Serbian authorities, nor its officials or any other institution."
Djukanovic, 54, is the only Balkan leader to have held onto power since the collapse of Yugoslavia began in the early 1990s, serving several times as prime minister and once as president in the country.
But analysts say he is now under pressure, with critics accusing his government of cronyism, corruption and links to organised crime.
His win without a majority will likely usher in a lengthy period of negotiation and a "period of instability", said political analyst Srdjan Vukadinovic.
The results should hand Djukanovic 36 seats in the 81-seat parliament, meaning he will have to court parties representing Croatian, Bosnian and Albanian minorities.
- Opposition urged to stay calm -
Turnout was around 72 percent and international observers said fundamental freedoms were largely respected, but added that there were areas of concern.
"Allegations of corruption, foreign funding, political tension and inconsistencies in the legal framework tainted the electoral environment. Despite this, the verdict of our observers is that the elections represented the will of the people," said Aleksander Pociej of the Parliamentary Assembly Council of Europe's observation mission.
Barricades have been erected near parliament, apparently to protect the building against any post-election violence.
Opposition leader Andrija Mandic urged his supporters to stay calm and Interior Minister Goran Danilovic, who also belongs to an opposition party, urged pro-government voters not to head into the streets to celebrate.
Montenegro was invited to join NATO in December, and ratification of the deal will be put to the next parliament.
But the issue profoundly divides the country, prompting reminders of the bonds with Russia and the alliance's 1999 bombing of Yugoslavia.
Moscow, already angered by EU sanctions over the Ukraine conflict, has warned of consequences if the Adriatic republic joins NATO.