In exchange, Washington has agreed to lift sanctions against several Belarusian companies, according to an anonymous U.S. official.
Since taking office last year, U.S. President Donald Trump has begun building ties with Belarus, a close ally of Russia. He has eased sanctions on the country and even invited it to his so-called peace council.
Belarus has released prisoners in several rounds in recent months, partly after American efforts.
Among those released on Thursday are human rights activists Valentin Stefanovich, Marfa Rabkova, and Anastasiya Loyka, according to the human rights organization Vyasna.
