Russian authorities have outlawed Amnesty International, meaning involvement with the human rights group is now a criminal offence.
The decision by the prosecutor general's office is the latest crackdown on Kremlin critics, journalists and activists that intensified after Moscow invaded Ukraine in February 2022.
In its statement, the office labelled Amnesty International as an "undesirable organisation" and accused it of being a "centre for the preparation of global Russophobic projects".
The designation means the group must stop any work in Russia, and anyone who cooperates or supports it could face prosecution. That includes if anyone shares Amnesty's reports on social media.
The office also accused Amnesty of intensifying the military confrontation between Russia and Ukraine.
"They justify the crimes of Ukrainian neo-Nazis, call for an increase in their funding, and insist on the political and economic isolation of our country," the statement added.
Russian officials regularly accuse Ukraine of being dominated by "neo-Nazis", an accusation widely seen in the West as baseless propaganda.
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Amnesty did not immediately reply to a request by Sky News for comment, but Human Rights Watch - another international civil rights group - said the ban "simply highlights Russia's ambition to hide the truth about human rights violations".
Rachel Denber, deputy director of the Europe and Central Asia division, told Sky News: "This designation is nothing more than an attempt by authorities to intimidate and deter Russian citizens from supporting or cooperating with this prominent, deeply respected organisation."
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Another independent group, the International Service for Human Rights, said: "We deplore the effective criminalisation of Amnesty International in Russia."
"The banning of Amnesty in Russia just proves that there are dark, corrupt and criminal places and practices that [Vladimir] Putin doesn't want the world to see," executive director Phil Lynch told Sky News in a statement.
Founded in 1961 and headquartered in London, Amnesty International campaigns for human rights across the world, including on behalf of those it designates prisoners of conscience.
Campaigns supporting Russian rights
In recent years, Amnesty International has released reports on Russia's war in Ukraine, accusing Moscow of crimes against humanity.
It has also spoken out against the Kremlin's crackdown on dissent that has swept up thousands of people in recent years.
Russia's list of "undesirable organisations" currently covers 223 entities, including prominent independent news outlets and rights groups.
They include Radio Free Europe/Radio Liberty or Russian independent outlet Meduza, think tanks like UK-based Chatham House, anti-corruption group Transparency International and opposition group, Open Russia.
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