(Reuters) – Russia said on Thursday that it was difficult to exchange prisoners with the United States and suggested Washington be silent about the fate of Brittney Griner, the U.S. basketball star detained in Russia on drugs charges. Referring to a letter that U.S. President Joe Biden intends to send to Griner according to NBC news, Deputy Foreign Minister Sergei Ryabkov said that “hype” around the case does not help, and that “this kind of correspondence does not help”. The United States and Russia swapped prisoners in late April when Moscow released former U.S. marine Trevor Reed from a Rus…