Speaking to CNN on condition of anonymity, one man who recently fled Chechnya after being arrested said hundreds of gay men like him are being rounded up by the authorities and held in appalling conditions in least three detention centers.
"My car got stopped at a Chechen police checkpoint and they asked me for my documents," said the man, who asked to be identified as "Ahmed."
Gay activists say sexual minorities have for years been targeted in conservative Chechnya.
One man shared a cellphone video with CNN which he said showed a friend being abducted and beaten by uniformed men more than a year ago.
Activists report mass arrests, abuse
In recent weeks, activists say the problem has become much worse, with hundreds of gay men being detained and subjected to horrifying abuse.
"They started beating me with their fists and feet. They wanted to get names of my gay friends from me," another Chechen man told CNN at a safe house where we arranged to meet.
"Then they tied wires to my hands and put metal clippers on my ears to electrocute me. They've got special equipment, which is very powerful. When they shock you, you jump high above the ground."
The mainly Muslim republic is run by Ramzan Kadyrov, a Kremlin-backed strongman, whose security forces are accused by human rights groups of abductions, killings and other abuses.
A Chechen government spokesman called the allegations of a gay crackdown in Chechnya "an absolute lie," and denied gay men exist in the republic.
Video footage has emerged of Chechen clerics delivering an angry sermon in Grozny, Chechnya's main city, condemning the allegations, and promising "retribution."
Haley: Anyone involved must be held accountable
One major Russian newspaper, Novaya Gazeta, which first reported the story, says "its entire staff" is now at risk of reprisals.
Russia has a checkered record on gay rights, breaking up gay pride marches and even passing anti-gay propaganda laws.
But the strong allegations emerging from Chechnya are unprecedented and have provoked an international backlash.
"We continue to be disturbed by reports of kidnapping, torture, and murder of people in Chechnya based on their sexual orientation," read a statement from Nikki Haley, US ambassador to the United Nations.
"If true, this violation of human rights cannot be ignored -- Chechen authorities must immediately investigate these allegations, hold anyone involved accountable, and take steps to prevent future abuses," the statement said.
So-called honor killings widespread
The men from Chechnya who spoke to CNN insisted their biggest concern was being outed as gay by the Chechen authorities.
Being gay is considered by many in the region to be shameful and in Chechnya the practice of so-called honor killings -- murder by family members to expunge shame -- is widespread.
"If my family finds out that I'm gay, then no authorities, no troops are needed. They will kill me themselves," says Ahmed.
"Even if my parents will forgive me, someone -- like my uncle -- won't forgive," he said.
It is that fear of family retribution, amid reports of an official crackdown, that is now forcing many gay Chechens to flee their homes.