The government's top spokesman said Monday that Belarus should be condemned if it actually forced a commercial airliner to land so a journalist aboard could be arrested.
Media reports said Belarusian authorities diverted a Ryanair plane to Minsk and detained dissident journalist Roman Protasevich, who was on board. The plane was flying from Athens to Lithuania.
"We are still confirming what happened," said Chief Cabinet Secretary Katsunobu Kato at a news conference. "If they arrested a passenger on board the aircraft for a reason not associated with the operation or the landing instruction of the aircraft, we believe they should be strongly condemned."
The European Union has called it a hijacking and threatened sanctions on Belarus, while the United States has also criticized the forced landing and arrest.
The International Civil Aviation Organization said it is "strongly concerned by the apparent forced landing of a Ryanair flight and its passengers, which could be in contravention of the Chicago Convention," or the Convention on International Civil Aviation.
Protasevich, a founder of the online news service NEXTA, which broadcast footage of mass protests against Belarusian President Alexander Lukashenko last year, initially fled to Poland and was recently based in Lithuania, according to the reports.
Belarus scrambled a fighter jet and flagged what turned out to be a false bomb alert to force the passenger aircraft to land, they said.