Belarus opposition politician Maria Kolesnikova has spoken out about how security officers put a bag over her head and threatened to kill her when they tried to forcibly deport her to Ukraine earlier this week.
The allegations are part of a complaint filed by her lawyer on Ms Kolesnikova, one of the most prominent leaders of month-long protests against the re-election of President Alexander Lukashenko. She prevented the attempt to expel her by tearing up her passport.
Ms Kolesnikova has emerged as a hero for the protest movement trying to bring down the curtain on Mr Lukashenko's 26-year rule, and a chief target for the authorities who have detained her over accusations of an illegal attempt to seize power in the former Soviet republic.
She said in her statement that she had genuinely feared for her life during the failed deportation attempt.
"In particular it was stated that if I did not voluntarily leave the Republic of Belarus, I would be taken out anyway, alive or in bits. There were also threats to imprison me for up to 25 years," Ms Kolesnikova said.
She was told there would be problems for her while she was held under guard or in jail.
"The persons indicated (security officers) uttered threats to my life and health, which I took to be real," she said.
Her lawyer Lyudmila Kazak filed a criminal complaint against Belarusian authorities including the KGB security police, for kidnap, illegal detention and threats to commit murder, the news portal Tut.By said.
The complaint was submitted to the state Investigative Committee. Asked for comment, a representative of the Committee, Sergei Kabakovich, said: "At the present moment I have no information about this."
Ms Kolesnikova's complaint included the names and ranks of individual officers of the KGB and the organised crime agency whom she accuses of threatening her, and said she would be able to identify them, it said.
She is now being held in the capital Minsk, where Ms Kazak said she was being questioned yesterday. Ms Kazak saw her client at a pre-trial detention centre on Wednesday, and said she had bruises on her body.
Mr Lukashenko denies rigging the August 9 election, which official results said he won by a landslide, and has cracked down hard on protesters demanding his resignation.
He has refused to talk to the opposition, saying it is bent on wrecking the country.
Inaugurating a new chief prosecutor yesterday, he reiterated his uncompromising line.
"I want to tell you like a man... People often reproach me: 'He won't give up power.' They're right to reproach me. The people didn't elect me for this," he said.
"Power is not given to be taken, thrown and given away," he added, saying the country must not return to the chaos of the 1990s following the break-up of the Soviet Union.
In the month since the disputed election, nearly all the opposition's key leaders have been arrested, fled, or been forced to leave the country.
Writer Svetlana Alexievich, winner of the 2015 Nobel Prize in Literature, accused the authorities of terrorising their own people. Diplomats from seven European countries came to her flat, in part to help protect her.
Mr Lukashenko, in power since 1994, retains the support of his key ally, Russian President Vladimir Putin.
The West has so far been cautious about taking firm action that might provoke a Russian intervention.
Meanwhile, Polish Prime Minister Mateusz Morawiecki has described recent events in the neighbouring country as a "breakthrough".
"Belarusians have not only broken through their own fear, but they have shown the whole of Europe that they want to belong to a Europe of free, democratic, nations under the rule of law," he said.
He spoke ahead of a meeting in Warsaw with the leader of the Belarusian opposition, Svetlana Tikhanovskaya, who has been forced into exile in Lithuania.