GENEVA — Russian officials on Thursday pledged to prosecute anyone implicated in a prisoner-abuse scandal, but they failed to convince United Nations human rights experts that their promises signaled a change in official attitudes on torture.

Russia’s deputy justice minister, Mikhail Galperin, told the United Nations Committee Against Torture on Thursday that Russian authorities had arrested five prison guards who are suspected of torturing a prisoner in a penal colony northeast of Moscow in June 2017, and dismissed 17 officials.

The abuse was captured in a chilling 10-minute video filmed on a body camera and released online last week by Novaya Gazeta, an independent newspaper, showed uniformed guards holding down a naked, handcuffed prisoner, later identified as Yevgeny Makarov, while they ferociously beat his feet with truncheons and fists as he howled for them to stop.

Mr. Makarov’s lawyer, Irina Biryukova, who released the video to the newspaper, subsequently fled the country with her family, saying she had received death threats.