"We continue to see disturbing movements of Russian troops in western Russia and near Ukraine," RIA Novosti quoted Kirby as saying at a briefing.
He added that the American side is calling on Russia to "clarify its intentions."
Earlier, the Russian Foreign Ministry called a "fake campaign" a series of publications in American online publications that Moscow is allegedly pulling forces to the Ukrainian border.
In the Kremlin, media reports were called substandard stuffing.
At the same time, they recalled that Russia "maintains a military presence on its territory where it considers it necessary."
Also in Kiev, they said that the office of the Ukrainian leader has no information about the alleged pulling of Russian troops to the borders of the state.
As the head of the US Joint Chiefs of Staff Mark Milli noted, the United States does not see aggression in Russia's actions near the border with Ukraine.