Belarusian President Alexander Lukashenko freed 123 prisoners on Saturday including Nobel Peace Prize winner Ales Bialiatski and leading opposition figure Maria Kalesnikava after two days of talks with an envoy for President Donald Trump, a US statement said.
In return, the US agreed to lift sanctions on Belarusian potash. Potash is a key component in fertilisers, and the former Soviet state is a leading global producer.
The prisoner release was by far the biggest by Lukashenko since Trump's administration opened talks this year with the veteran authoritarian leader, a close ally of Russian President Vladimir Putin.
Western governments had previously shunned him because of his crushing of dissent and backing for Russia's war in Ukraine.
Bialiatski, co-winner of the 2022 Nobel peace prize, is a human rights campaigner who fought for years on behalf of political prisoners before becoming one himself. He had been in jail since July 2021.
Also freed were Kalesnikava, a leader of mass protests against Lukashenko in 2020, and Viktar Babaryka, who was arrested that year while preparing to run against the president in an election.
US officials have told Reuters that engaging with Lukashenko is part of an effort to peel him away from Putin's influence, at least to a degree - an effort that the Belarus opposition, until now, has viewed with extreme scepticism.
Trump's envoy, John Coale, had earlier told reporters in Minsk: "Per the instructions of President Trump, we, the United States, will be lifting sanctions on potash."
The US and the European Union imposed wide-ranging sanctions on Belarus after Minsk launched a violent crackdown on protesters following a disputed election in 2020, jailing nearly all opponents of Lukashenko who did not flee abroad.
Sanctions were tightened after Lukashenko allowed Belarus to serve as a staging ground for Russia's invasion of Ukraine in 2022.

Shooting at Australia's Bondi Beach kills 12
Police hold person of interest after Brown University shooting leaves two dead
Hamas says Israel's killing of senior commander threatens ceasefire
Ukraine's Zelenskyy ditches NATO ambition ahead of peace talks
Thailand declares curfew along coast as Cambodia border fighting spreads
