Russia has accused the United States and NATO of “provocative activities” in the waters and the airspace of the strategic Black Sea.
The Interfax news agency cited Russian Defense Minister Sergei Shoigu as making the comment on Tuesday, also accusing Kiev of trying to destabilize the situation in Ukraine's eastern Donbass region.
The accusations were made amid escalating tensions between Moscow and the West over Ukraine in recent weeks.
The US and its Western allies have expressed concerns regarding Russia’s military build-up along Ukraine’s borders as well as in the Crimean Peninsula, with the Kremlin saying its troop deployments are in response to "threatening" military action by NATO.
Kiev and Moscow have traded blame in the past weeks for a spike in violence in the Donbass, where Ukrainian troops and pro-Russian forces have been fighting since 2014.
The armed confrontations began when a wave of protests in Ukraine overthrew a democratically-elected pro-Russia government and replaced it with a pro-West administration. The majority in those areas refused to endorse the new administration.
That new government then began a crackdown on the mainly ethnic Russians in the east, who in turn took up arms and turned the two regions of Donetsk and Lugansk — collectively known as the Donbass — into self-proclaimed republics.
Kiev and its Western allies accuse Moscow of having a hand in the crisis. Moscow, however, denies the allegations.
Relations between Moscow and Kiev further deteriorated when the Black Sea peninsula of Crimea rejoined Russia following a referendum in 2014. More than 90 percent of the participants in the referendum voted in favor of that unification.