Some EU leaders have called the incident a hijacking, the Lithuanian president has called it a state-sponsored terrorist attack.
Belarus President Alexander Lukashenko personally ordered a passenger plane with a destination for Lithuania to land in Minsk.
On board was the regime critic Roman Protasevich who was arrested.
His girlfriend, Sofia Sapega, is also said to have been arrested.
Now Ryanair's CEO, Michael O'Leary, says that the passengers and crew were guarded by armed people and had their belongings searched.
"It was very scary for the crew and the passengers," he said, according to Reuters.
False bomb alarm
Belarus is now accused, on false grounds, of sounding a bomb on the plane to force the plane to the ground and then arresting the opposition journalist, something the EU condemns.
O'Leary describes the incident as a state-sponsored hijacking and talks about his suspicions.
- We believe that KGB agents were on the plane.
Several left the plane
He is not alone in believing that.
Irish Foreign Minister Simon Coveney also shares the view that several people who may be KBG agents have left the plane after landing in Belarus.
Five or six people left the plane immediately.
Only one of them was arrested, which indicates that the others were agents, he says.
Spokesmen for Belarus' President Aleksandr Lukashenko say, however, that it was really about the president receiving information about a bomb threat, and the Foreign Ministry claims that the country's authorities acted "in accordance with international rules".
According to Deputy Chief of Air Force Andrei Gurtsevich, the flight crew made the decision to land in Minsk.
However, Ryanair announces in a statement that Belarusian air traffic control ordered the plane to land in the capital.
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"We were treated normally but we did not receive any information," said one of the passengers on flight FR4978.
Photo: Reuters