Russia's Supreme Court has ordered the closure of Memorial, the country's most prominent rights group, which chronicled Stalin-era purges and symbolised post-Soviet democratisation.
Judge Alla Nazarova ordered the closure of Memorial International, the organisation's central structure, and its regional branches for failing to mark all of its publications with a label of "foreign agent" as required by law.
The "foreign agent" legislation, which carries Stalin-era connotations, brands organisations receiving funds from overseas as acting against Russia's interests.
"Disgrace! Disgrace!" some supporters shouted in court after the ruling.
Prosecutors also accused Memorial International of denigrating the memory of the Soviet Union and its victories and rehabilitating "Nazi criminals".
During this morning's hearing, a prosecutor said Memorial "creates a false image of the USSR as a terrorist state and denigrates the memory of World War II".
The court decision is the hardest blow yet to the organisation founded in 1989 by Soviet dissidents including Nobel Peace Prize laureate Andrei Sakharov.
Lawyer Maria Eismont said the shutdown was a "very bad sign" but added that Memorial would appeal and press ahead with its work.
"This is not the end," she told reporters.
Dozens of supporters gathered outside the courthouse in freezing temperatures and several people were detained. After the ruling, police demanded that members of the public and journalists disperse.
Memorial is a loose structure of locally registered organisations, with Memorial International maintaining the network's extensive archives in Moscow and coordinating its work.
The group has spent years cataloguing atrocities committed in the Soviet Union, especially in the notorious network of prison camps, the Gulag.
The move against Memorial caps a year that has seen authorities jail President Vladimir Putin's top critic Alexei Navalny, outlaw his organisations and crack down on independent media and rights groups.
But the ban against Memorial International stands out even in the current climate and would have been unimaginable just a few years ago.
