Belarus freed top opposition figure Sergei Tikhanovsky and more than a dozen other political prisoners Saturday following an appeal from the White House, Minsk said, a sign of warming ties between Washington and Belarus-ally Moscow.

U.S. special envoy Keith Kellogg met Belarusian President Alexander Lukashenko in Minsk, the highest-profile visit of a U.S. official to the authoritarian state in years.

Sergei Tikhanovsky, the husband of Belarus' opposition leader, has called on US President Donald Trump to "just say the word" and ask for all political prisoners in Belarus to be released.