GENEVA (Reuters) - Russia must halt torture of detainees and prosecute the perpetrators, including prison guards caught on video beating an inmate, United Nations human rights investigators said on Friday.

The U.N. Committee against Torture, in a rare move, told Russian authorities to report back in a year on progress in holding to account guards who beat Yevgeny Makarov with truncheons and their superiors who suppressed the year-old tape, which provoked a public outcry.

Despite “numerous reliable” reports of torture, they rarely lead to prosecutions, or those responsible are charged with simple abuse of authority rather than a crime, said panel member Claude Heller.

“The strengthening of the rule of law would be in a certain sense our main recommendation,” Heller told a news briefing.

Jens Modvig, panel chairman, said: “One could get the impression that the prison system in Russia is almost a state in the state and is not really being scrutinized from the outside. The prison system should be better monitored with a view to preventing the episodes that we see repeatedly.”

The Novaya Gazeta newspaper published the notorious 10-minute video clip last month and said the incident took place in June 2017 in a prison in the city of Yaroslavl, northeast of Moscow.

Russian deputy justice minister Mikhail Galperin told the committee last month that authorities would prosecute the guards. This would become a “very clear signal on the unacceptability of torture”, he said.

Several officials have been removed from their jobs in connection with the case and 11 are in custody, authorities said.

Arrests in the case were a “good start”, Modvig said. “Sometimes investigations are stopped or find no violations of any kind. It remains to be seen how Russia will deal with this case,” he added.

The U.N. panel, composed of 10 independent experts, called on Russian authorities to protect Makarov, and his lawyer Irina Biryukova who has fled the country, against reprisals.

Russia must “combat impunity concerning torture and ill-treatment cases, including by ensuring that high-level government officials publicly and unambiguously affirm that torture will not be tolerated”, it said.

The experts had received “consistent and numerous reports indicating the lack of prompt, impartial and effective investigation into allegations of torture or ill-treatment”.

Some 600,000 people are held in nearly 1,000 prisons and detention centers across Russia, with 4,000 deaths from various causes recorded each year, “one of the highest rates in the Council of Europe countries”, Modvig said.