The Russian Defense Ministry says the United States is setting up a multinational group of armed forces close to Russia's eastern border in the Black Sea region.
The ministry was reported by Russia's TASS news agency on Tuesday as saying that the US navy's guided missile destroyer Porter, tanker vessel John Lenthall, and command ship Mount Whitney were currently deployed to the Black Sea to take part in multinational drills that the US European Command is holding in the strategic region.
Two US Air Force B-1B long-range strategic bombers were reported by the ministry to have performed flights over the Black Sea at a distance of 100 km from the Russian state border.
"These are unscheduled moves by the US military, that is setting up a multinational group of armed forces in close proximity to the Russian border," the Russian Defense Ministry said in the statement, adding that such moves were a destabilizing factor in the region and pursued the goal of the military exploitation of Ukrainian territory.
"Considering that in addition to the US navy, the drills will involve tactical, patrol and strategic aircraft, and also the contingents of the armed forces of Bulgaria, Georgia, Romania, Turkey, and Ukraine, this is evidence of an attempt to study the prospective theater of military operations in case that Kiev prepares a use-of-force scenario in the southeast," the statement said.
The ministry said the country's armed forces were continuously and closely monitoring the situation, adding that Russia's Black Sea Fleet was carrying out a set of measures to track the US warships' deployments in the area.
The US navy announced early last week that the amphibious command ship USS Mount Whitney had arrived in the Turkish city of Istanbul and would soon join forces with guided-missile destroyer USS Porter as well as other NATO ships in the Black Sea.
Russian President Vladimir Putin criticized the US-led NATO activity near Russia's borders and said his country's military could observe Mount Whitney "through binoculars or in the crosshairs of its... defense systems."
Putin and other top Russian officials have previously warned that the expansion of NATO activities in Ukraine represents a "red line" for Moscow.
The Russian navy said in a statement last Tuesday that the Black Sea Fleet had rehearsed destroying mock enemy targets during drills in the sea amid the presence of US warships and NATO forces in the strategic region.
The Russian media also reported that the fleet's air defense systems had been put on alert at its bases in the port city of Novorossiysk and on the Crimean Peninsula.
Russia has repeatedly accused NATO of carrying out provocative activities close to its borders.