International organizations are demanding Russia investigate the abduction, detention and killing of gay and bisexual men in the country’s southern republic of Chechnya.

United Nations human rights experts on Thursday called on Russian authorities to “put an end to the persecution of people perceived to be gay or bisexual in the Chechen Republic who are living in a climate of fear fueled by homophobic speeches by local authorities.”

“It is crucial that reports of abductions, unlawful detentions, torture, beatings and killings of men perceived to be gay or bisexual are investigated thoroughly,” they added.

The appeals follow reports in the respected Russian newspaper Novaya Gazeta that police in the predominantly Muslim republic of Chechnya have rounded up more than 100 men suspected of homosexuality and that at least three of them have been killed.

Chechen authorities have denied the reports, while a spokesman for leader Ramzan Kadyrov insisted there were no gay people in Chechnya.

“Nobody can detain or harass anyone who is simply not present in the republic,” Alvi Karimov told the Interfax news agency. “If such people existed in Chechnya, law enforcement would not have to worry about them since their own relatives would have sent them to where they could never return.”

Separately, the director of the human rights office at the Organization for Security and Cooperation in Europe, Michael Georg Link, said Thursday that Moscow must “urgently investigate the alleged disappearance, torture and other ill-treatment” of gay men in Chechnya.

Novaya Gazeta also reported this month that Chechen authorities are running secret prisons, branded “concentration camps,” in the town of Argun where men suspected of being gay are kept and tortured.

After two separatist wars in the 1990s, predominantly Muslim Chechnya became increasingly conservative under late President Akhmat Kadyrov and then his son Ramzan.