According to several news agencies the American troops that are stationed in Poland are a threat to the national security of Russia according to the Kremlin. This is just another piece of evidence that the Obama administration has no respect for Russia and the willingness for Trump and Putin to improve relations between the two nations.
Russia has precedent to believe this is a threat from the United States, during the cold war Russia and the United States nearly had a nuclear war in 1962 over the Cuban missile crisis. At the end of the cold war NATO and Russia agreed that they wouldn’t advance toward each others borders militarily. The United States have done this repeatedly since the agreement and Russia has not retaliated, with the exception of the annexation of Crimea which from all reports the people of Crimea wanted to be a part of Russia. America has also imposed economic restrictions of Russia on a whim and still Putin has remained calm.
The Trump administration will be defusing the situation I believe. They will likely come to some agreement between the two of them which will have the result of increasing stability and a reduction in tension between the two powers.