A special prosecutor investigating an alleged plot to sway last month's election in Montenegro said on Sunday a group of "Russian nationalists" had planned to assassinate Prime Minister Milo Djukanovic to get an opposition party into power.

Montenegro, a former Yugoslav republic, has been abuzz with conspiracy theories since the Oct. 19 election, when authorities arrested 20 Serb citizens at the border with Serbia, accused of planning armed attacks against state institutions.

Opposition parties had said the suspected plot was fabricated and accused Djukanovic of using the security services to help extend his quarter century of dominance over Montenegro.