Belarus opposition politician Maria Kolesnikova said 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.
Kolesnikova, a prominent leader of month-long protests against the re-election of President Alexander Lukashenko, prevented the attempt to expel her by tearing up her passport. She is now in detention in the capital Minsk.
She said in the statement that she had genuinely feared for her life.
"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," Kolesnikova said.
Her lawyer said she was filing a criminal complaint against Belarusian authorities including the KGB security police.
Lukashenko denies rigging the August 9 election, which official results said he won by a landslide, and has cracked down hard on opponents demanding his resignation.
Iran and Israel targeted each other with missiles and airstrikes early on Saturday after Israel launched its biggest-ever air offensive against its longtime foe in a bid to prevent it from developing a nuclear weapon.
Israeli fire and airstrikes killed at least 35 Palestinians across the Gaza Strip, most of them near an aid distribution site operated by the US-backed Gaza Humanitarian Foundation, local health authorities said.
The death toll from the Air India plane crash in Ahmedabad rose to 270 on Saturday, as grieving families expressed frustration over delays in the release of victims' bodies, many of which were badly charred in the tragedy.
US President Donald Trump urged Iran on Friday to make a deal on its nuclear programme before it faced more attacks from Israel that he said would be "even more brutal."
Israel launched widescale strikes against Iran on Friday, saying it targeted nuclear facilities, ballistic missile factories and military commanders and that this was start of a prolonged operation to prevent Tehran from building an atomic weapon.