Russian military aircraft were scrambled to head off a US warship that was acting "aggressively" in the Black Sea, state news agency RIA has reported.
The reports were made by an anonymous source in Russia's armed forces in Crimea,
The source was quoted as saying that the guided missiles destroyer USS Ross was moving along the edge of Russia's territorial waters and heading in their direction on Sunday (31 May)
"The crew of the ship acted provocatively and aggressively, which concerned the operators of monitoring stations and ships of the Black Sea Fleet," RIA quoted the source as saying.
"Su-24 attack aircraft demonstrated to the American crew readiness to harshly prevent a violation of the frontier and to defend the interests of the country."
The Pentagon has denied any unusual behaviour, stating that the Ross' deployment to the Black Sea had been publicly announced.
Pentagon spokeswoman Eileen Lainez said the USS Ross was "well within international waters at all times, performing routine operations".
"The US navy operates routinely in the Black Sea, in accordance with international law."
Russia's defence ministry was not immediately available to comment on the report.
The incident is the latest example of encounters between Russian and Western militaries, as tensions continue over the crisis in Ukraine, and Russia's annexation of the Crimea peninsula, home to Russia's Black Sea Fleet, last year.
Earlier this month, both Britain and Sweden said they had scrambled fighters to intercept Russian bombers near their territory.
The United States said last month that it was filing a complaint to Russia over a Russian fighter's "sloppy" and unsafe interception of a US reconnaissance plane in international aerospace over the Baltic Sea.