Montenegro's Foreign Ministry on Thursday ordered four Russian diplomats to leave the country over violations of diplomatic norms, the Podgorica-based Pobjeda newspaper reported, citing sources from the ministry.
A diplomatic note has been handed over to Russia's ambassador to Montenegro and the diplomats have a week to leave the country, the report said.
Officials from Montenegro's Foreign Ministry and the Russian embassy could not immediately be reached for comment.
The government of Montenegro, a small ex-Yugoslav republic of just 628,000, has joined international sanctions against Russia over its invasion of Ukraine.
Montenegro already expelled one Russian diplomat in March, again citing violations of diplomatic norms.
North Macedonia and Slovenia, both ex-Yugoslav republics and NATO members, have also expelled a number of Russian diplomats.
On Feb 24, Russian President Vladimir Putin sent his troops into Ukraine on what he calls a "special military operation" to demilitarise and "denazify" Ukraine.
Ukraine and the West say Putin launched an unprovoked war of aggression.
(Reporting by Aleksandar Vasovic; Editing by Kirsten Donovan)