The Kremlin has tried to calm tensions in a feud between Trump and Medvedev that spiraled into nuclear threats.

Russia said on Monday that everyone should be "very, very careful" about nuclear rhetoric, responding to a statement by U.S. President Donald Trump that he had ordered a repositioning of U.S. nuclear submarines.

President Trump announced Friday on social media that he ordered two nuclear submarines to move into more strategic positions near Russia. On Monday, Russian officials downplayed the comments and warned about the risk of nuclear rhetoric.