The Olympic saga came as police in Ukraine said a missing Belarusian activist, whose NGO helps his compatriots flee the country, had been found hanged in a park in Kiev
"This is a retrograde and disappointing development," Walsh said in a statement issued by the International Air Transport Association, which counts most of the world's major airlines among its 293 members.
The TV footage showed Protasevich -- who could face 15 years in jail -- with dark markings on his forehead, saying he was being treated "according to the law."
As the demonstrations subsided, activists, protesters and journalists were prosecuted and the court system has since become a conveyor belt of guilty verdicts.
More than 200 trucks a day cross into European Union member Latvia at the Paternieki border point, some of them stuffed with smuggled cigarettes hidden among other cargo.
"Despite the tensions in society artificially created by external forces, we survived," Lukashenko said, adding that Belarus "will hold out no matter what".
The Nexta Telegram channel, which mobilised and coordinated demonstrators over the months of rallies, called for fresh demonstrations on Thursday and Friday when the assembly will be in session.
The measures, to be formalised with the publication of the list on Thursday, will be the third round of sanctions the European bloc has imposed on the regime of Belarus President Alexander Lukashenko.