Russia's Supreme Court on Tuesday ordered the closure of Memorial International, a prominent human rights organization, in the latest blow to the country's shrinking civil society.

Memorial International studies historical abuses by the former Soviet Union and, according to its website, aims to bring to light truth about its victims and offer support to their families. The group's lawyer, Tatiana Glushkova, confirmed the ruling to CNN and said the group would appeal the decision.

"The real reason for Memorial's closure is that the prosecutor's office doesn't like Memorial's work rehabilitating the victims of Soviet terror," Glushkova told CNN.

The Prosecutor General's Office of Russia requested Memorial International be liquidated in November.

The group was accused of repeatedly breaking the law for failing to mark all its publications with a compulsory "foreign agent" warning.

The Justice Ministry had designated the group a foreign agent in 2016, using a law targeting organizations receiving international funding.

Videos posted on social media showed Memorial supporters shouting, "Shame, shame!" in the court's hallways and at the entrance to the building shortly after the ruling.

Memorial's representatives argued there were no legal grounds for the group's closure, and critics say the Russian government targeted Memorial for political reasons.

Nobel Peace Prize winner Andrei Sakharov was one of the group's original founders and the first honorary chairman of the Memorial Society.

Memorial International's sister organization, the Memorial Human Rights Center, is facing a similar challenge. Prosecutors in Moscow charged the group with justifying terrorism and extremism in its publications. A case on its closure is before the Moscow City Court and its next hearing is scheduled for Wednesday.

The Memorial Human Rights Center is a separate legal entity that focuses on oppression in modern Russia. It was labeled a foreign agent in 2014, according to Human Rights Watch.

The Supreme Court's decision was not unexpected.

Russian President Vladimir Putin, in a speech earlier this month, accused Memorial of supporting groups that are blacklisted as "as terrorist and extremist organizations."

"Its violations were blatant," he said. However, Putin did add that Memorial was "indisputably" one of Russia's most "reputable" NGOs.

Democratic and human rights groups have been targeted for years under Putin's authoritarian regime.

Thousands of protesters were detained earlier this year for taking part in several demonstrations supporting Alexey Navalny, the country's best-known opposition to Putin.

Demonstrations during the first few months of 2021 were met with a strong crackdown by police, including widespread arrests and an alleged disproportionate use of force.

But experts worry that shuttering Memorial could be a harbinger of worse to come for any groups that fall afoul of the Kremlin.

"It is difficult to overstate the urgency of ensuring that the two Memorial entities can continue their crucial work protecting human rights," several rights groups, including Human Rights Watch and Amnesty International, wrote in an open letter published in early December.

"Memorial is at the very heart of Russia's civil society, and by targeting it, authorities are hoping to destroy Russia's civil society at large."

Mary Lawlor, the UN Special Rapporteur on the situation of human rights defenders, said in a statement earlier this month that a dissolution of Memorial would be "a new low for human rights defenders in Russia."

"Just as its creation marked the beginning of openness in Russia, its closure might signal an end to this period," Lawlor said.

"Their criticism of historical and contemporary human rights abuses has for many years made them the target of a government that is ever diminishing the space for public debate."