Western powers prepared to pile sanctions on Belarus and cut off its aviation links on Monday, furious after it scrambled a warplane to intercept a Ryanair aircraft and arrest a dissident journalist, an act one official denounced as "state piracy."

In a video posted online, the detained blogger, Roman Protasevich, 26, said he was in good health, being held in a pretrial detention facility in Minsk, and acknowledged having played a role in organizing mass disturbances in the capital last year.

In the video on the Telegram messaging app, he wore a dark sweatshirt and clasped his hands tightly in front of him. The comments were immediately dismissed by his allies, including his father, as having been made under duress.