The "unionists," seeking continued confederation with much-larger Serbia, and the "sovereignists," claiming Montenegro's historical right of independence, have stepped up their campaigns before the Sunday vote, accusing one another of working against Montenegro's interests.
Rivals hurled stones at each other over the weekend in the northern town of Pljevlja, and burned a car belonging to a unionist politician, prompting fears that the referendum could trigger violence reminiscent of the 1990s breakup of Yugoslavia.
Hundreds of policemen were deployed late Monday to the central Montenegrin town of Niksic, the birthplace of Montenegro's pro-independence leader Milo Djukanovic, to keep angry pro-independence crowds from attacking the unionists.
People wearing T-shirts with "Da," or "Yes," for independence have been beaten by those opposing the separation in Rovci village. Red flags with a golden eagle, used by Montenegro during its 1878-1918 independence, as well as red-white-and-blue union flags have been torched throughout the campaign.
The European Union's envoy for the referendum, Miroslav Lajcak, said in Montenegro's capital Podgorica Tuesday that the incidents "are not the result of some organized actions."
Montenegro's 650,000 population is almost evenly split over the future of their mountainous republic, nestled at the southern corner of the Adriatic Sea, the AP reports.
Serbia and Montenegro - both majority Christian Orthodox and speaking the same language - are the only two former Yugoslav republics that stayed together when the six-member federation broke up in the series of bloody conflicts in the 1990s in Slovenia, Croatia and Bosnia.
The FSB of Russia has distributed the footage of video surveillance over suspects, who allegedly worked to orchestrate a military coup in Belarus and planned to assassinate its president, Alexander Lukashenko