The Kremlin has declined to accept outright the names of men reported to have been murdered in Chechnya.
Novaya Gazeta, an investigative newspaper based in the region, has published the names of 27 men killed in one night.
The secret mass execution is thought to have seen up to 56 people killed – all without trial.
However the Kremlin says the news is unsubstantiated.
Responding to the published list, Russian President Vladimir Putin’s spokesman, Dmitry Peskov said: “We have taken note of [the reports].”
In an address to journalists, he added: “We have similarly taken note of the denials of this information by Chechen law enforcement bodies.
“The information is of an anonymous character. It’s unclear what the source of this information is.
“So this is all I can say for now.”
According to newspaper Novaya Gazetta, the executions were all carried out in Chechnya’s capital, Grozny, on the night of 25 January.
The strongly anti-Putin publication says mass arrests and executions in the Muslim region were triggered by the killing of a policeman on 16 December 2016.
It reports that the victims were shot without trial, then the bodies were “taken to various cemeteries, including Christian ones, where they were buried in hastily dug graves”.
The Russian LGBT Network confirmed that a number of the men killed were gay and bisexual, but some are believed to have been heterosexual.
“As far as we know, the information in the Novaya Gazeta regarding 27 people being killed is true,” a representative for the group said.
“With regards to the sexual orientation of those killed, as far as we know there are homosexual people in this list, but not all of them at all.”
The outlet has spent months investigating illegal detentions in the area.
The same newspaper broke the story that the region is rounding up and persecuting gay people earlier this year.
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The ‘concentration camps’ were reportedly set up in February 2017, with gay men being abducted, held prisoner and tortured there.
Two camps were initially reported on, based in the villages of Argun and Tsotsi-Yurt, but further investigations revealed a further four jails for gay people, bringing the total number believed to be in the Chechen Republic up to six.
One was later destroyed and moved to a new location.
Explaining its reasons for publishing the harrowing list of 27 names, the paper wrote: “Two months we had hoped for cooperation at the very beginning [of the investigation]to be effective.
“Today it is obvious that the Investigative Committee of Russia is losing ground on this situation…
“That is why we publish the list of those who, according to our information, were victims of the worst possible extrajudicial executions in Grozny.
“And now the investigation, which has a lack of living of witnesses, will have to deal with the special witnesses.
“Because only the dead have nothing to fear in Chechnya.”