The dad of detained dissident journalist Roman Protasevich said he believes his son was forced in a video posted online to admit guilt and appeared to have a broken nose.
The Lithuania-based blogger and his female companion, Sofia Sapega, were both taken into custody after Belarus scrambled a warplane to intercept a Ryanair aircraft flying from Athens to Vilnius.
It was diverted to Minsk on Sunday in an action condemned by the European Union and the US.
Appearing on several channels of the Telegram messaging app on Monday, Mr Protasevich, 26, acknowledged playing a role in organising mass disturbances in Minsk last year.
To his dad, Dzmitry Protasevich, the video appeared to be a result of coercion.
“It’s likely his nose is broken, because the shape of it has changed and there’s a lot of powder on it.
“All of the left side of his face has powder,” he told Reuters in an interview in Russian on Monday from Wroclaw, Poland, where he and his wife live.
“It’s not his words, it’s not his intonation of speech. He is acting very reserved and you can see he is nervous.
“And it’s not his pack of cigarettes on the table – he doesn’t smoke these. So I think he was forced.”
He added: “My son cannot admit to creating the mass disorders, because he just didn’t do any such thing.”
Belarus’ Interior Ministry said Mr Protasevich was being held in jail and had not complained of ill health.
The 27 leaders of the European Union on Monday demanded his immediate release as well as an investigation by the International Civil Aviation Organization into the incident.
They also agreed to impose more sanctions on Belarus, called on their airlines to avoid Belarusian airspace and authorised work to ban Belarusian airlines from European skies and airports, a spokesman said.
The EU, along with the United States, UK and Canada had already imposed asset freezes and travel bans on almost 90 Belarusian officials, including President Alexander Lukashenko.
That followed an August election that opponents and the West say was a sham. The president has denied electoral fraud.
Since the disputed vote, authorities have rounded up thousands of his opponents, with all major opposition figures now in jail or exile.
“We are surprised that the destiny of one person means a lot, that it is seen as valuable to the European Union,” Dzmitry Protasevich said. “This is something that is lost in Belarus.”
“I think what happened was an act of revenge, to enlighten others: Look what we can do,” he said. “This is total insanity, what is going on.”
His social media feed from exile has been one of the last remaining independent outlets for news about the country since a mass crackdown on dissent last year.