Reports that authorities in Chechnya have been rounding up gay people have been verified by human rights groups.

Early reports emerged last week that gay people are being targeted in the region, which is part of Russia but has substantial autonomy.

Russian newspaper Novaya Gazeta reported that more than 100 gay men had been detained in the last two weeks “in connection with their non-traditional sexual orientation, or suspicion of such” as part of a purge.

Several people were also reportedly feared dead following violent raids.

There was initially little verification of the claims from the remote region, which is largely closed off from the centre of Russia.

However the reports have now been separately confirmed by Human Rights Watch and the International Crisis Group, both of which cite on-the-ground sources that appear to confirm gay men have been targeted for detention.

In its report, HRW confirmed: “The information published by Novaya Gazeta is consistent with the reports Human Rights Watch recently received from numerous trusted sources, including sources on the ground.

“The number of sources and the consistency of the stories leaves us with no doubt that these devastating developments have indeed occurred.”

Ekaterina L. Sokiryanskaya, Russia project coordinator for the International Crisis Group, told the New Tork Times: “I got numerous, numerous signals… it came from too many sources not to be true.”

“Even delivering the information is very difficult… they are just small islands, isolated.”

According to HRW, LGBT Network in Russia opened a special hotline to provide emergency support to those who find themselves in immediate danger.

A spokesman for the Chechen government, Alvi Karimov, previously denied the reports while claiming that gay people haven’t been targeted because “you can’t detain and harass someone who doesn’t exist in the republic”.

They said: “If there were such people in the Chechen republic, law enforcement wouldn’t have a problem with them because their relatives would send them to a place of no return.”

A spokesperson for the Kremlin denied any knowledge of a purge but claimed the Russian government would “investigate” the reports.

In the UK, activists have written to Foreign Secretary Boris Johnson, calling for the British government to intervene in the crisis.

The letter, signed by Pride in London’s Michael Salter and Alison Camps said: “Pride in London is alarmed to learn that authorities in the Russian republic of Chechnya have launched a campaign to identify and execute members of the LGBT+ community within the quasi-independent state, formally under Russian control.

“Pride in London would urge the UK Government to take meaningful steps to assist the LGBT+ community in Chechnya and to offer protection and support to what amounts to state sponsored genocide.

“The statements issued by the authorities in Chechnya, that LGBT+ citizens do not exist in the state, are a chilling indictment to the goals of an extermination agenda rather than that of fact.”

The Foreign Office responded to the pressure, telling BuzzFeed: “We are very concerned by reports of mass arrests of individuals in Chechnya due to their perceived or actual sexual orientation. We condemn any and all persecution.

“The human rights situation for LGBT people in Russia has deteriorated significantly in recent years and we have voiced our serious concern over these developments with Russian authorities at all levels.”

Related: Russian government warns citizens not to be homophobic while on holiday in Europe