American forces are currently deployed to the region for a series of exercises with NATO allies.
Moscow said it reserved the right to respond to Montenegro’s “hostile course,” while Washington praised the country for “choosing its own alliances.”
Russian President Vladimir Putin criticized the media, claiming it has stayed "silent" on U.S. and NATO military expansion.
The Russian president outlined the action he feels would be necessary and said Sweden would be no safer in NATO.
After many fallouts between Turkey and its European allies, 18 EU nations and Canada are reportedly vetoing plans to host NATO's next summit in Istanbul.
Russian lawmaker Vyacheslav Alekseyevich Nikonov said nuclear weapons would be necessary in the event of a U.S. or NATO invasion of Crimea or eastern Ukraine.
Russia and Belarus's neighbors are concerned about the huge drill they have planned.
The Latvian ambassador to Canada said he does not feel safe even as NATO forces arrive ahead of Russian war games simulating an attack on the West.
Defense Secretary James Mattis called Russia's missile moves "destabilizing" as Moscow positions for war games with Belarus.
A top Army general of U.S. and NATO's European forces said the Western military alliance is taking a wartime posture to Russia's rise to the world stage.
The head of the U.S. command in Europe asked lawmakers to consider deploying more troops and equipment to ward off Russian aggression.
Trump called NATO “obsolete” before concluding it was “no longer obsolete” last month.
Donald Trump's recent about-face on NATO didn't influence the long-planned delivery of the U.S.'s most advanced fighter jets.
Poland and the Baltic states of Estonia, Latvia and Lithuania were designated as venues for four major NATO battle groups.
Russia's condemnation follows President Donald Trump's statement that U.S.-Russia relations have hit a new low.
U.S. Strategic Command head Gen. John Hyten said the U.S. had "no defense" for Russia's SSC-8 nuclear-capable cruise missiles in Europe.
Russia fired missiles only miles away from NATO forces in the volatile Black Sea region, where the U.S. has accused Moscow of threatening its interests.
NATO has planned to spend over $3.2 billion on a large boost to the 28-member military alliance's electronic and satellite communication defense systems.
Moscow's attempts to regain influence in the Balkans shows the perils of backing off Russia.
Tillerson's potential no-show had increased unease caused by U.S. President Donald Trump's description of NATO as "obsolete" during his election campaign.