U.S. prosecutors charged four Belarusian government officials on Thursday with aircraft piracy for diverting a Ryanair flight last year to arrest an opposition journalist, using a ruse that there was a bomb threat.

The charges, announced by federal prosecutors in New York, recounted how a regularly-scheduled passenger plane traveling between Athens, Greece, and Vilnius, Lithuania, on May 23 was diverted to Minsk, Belarus by air traffic control authorities in Belarus.

“Since the dawn of powered flight, countries around the world have cooperated to keep passenger airplanes safe. The defendants shattered those standards by diverting an airplane to further the improper purpose of repressing dissent and free speech," U.S. Attorney Damian Williams said in a news release announcing the charges.

Ryanair said Belarusian flight controllers told the pilots that there was a bomb threat against the jetliner and ordered them to land in Minsk. The Belarusian military scrambled a MiG-29 fighter jet in an apparent attempt to encourage the crew to comply with the orders of flight controllers.

In August, President Joe Biden levied sanctions against Belarus on the one-year anniversary of Belarusian President Alexander Lukashenko’s election, in a vote the U.S. and international community said was fraught with irregularities.

The arrested journalist and activist, Raman Pratasevich, ran a popular messaging app that helped organize mass demonstrations against Lukashenko. The 26-year-old Pratasevich left Belarus in 2019 and faced charges there of inciting riots.

Lukashenko was awarded a sixth term leading the Eastern European nation last year. Widespread belief that the vote was stolen triggered mass protests in Belarus that led to increased repressions by Lukashenko’s regime on protesters, dissidents and independent media. More than 35,000 people were arrested and thousands were beaten and jailed.

Those charged in court papers were identified as Leonid Mikalaevich Churo, director general of Belaeronavigatsia Republican Unitary Air Navigation Services Enterprise, the Belarusian state air navigation authority; Oleg Kazyuchits, deputy director general of Belaeronavigatsia; and two Belarusian state security agents whose full identities weren’t known to prosecutors.