Russian authorities on Thursday turned the legal screws on one of the country’s most prominent human rights group as part of a months-long crackdown on activists, independent media and opposition supporters.

The Prosecutor General’s Office has petitioned Russia’s Supreme Court to revoke the legal status of Memorial — an international human rights group that rose to prominence for its studies of political repressions in the Soviet Union and was declared a “foreign agent” in 2016. The “foreign agent” label implies additional government scrutiny and carries strong pejorative connotations that can discredit the targeted organization.

The group tweeted Thursday that prosecutors accused it of systematically violating the “foreign agents” law, but didn’t give details about the alleged violations. In a statement on its website, Memorial’s board said there are no legal grounds for revoking the group’s legal status.

“We have repeatedly said that the (‘foreign agents’) law had been initially designed as an instrument for persecution of independent organizations, and insisted that it should be abolished,” the statement read. “This is a political decision to destroy the Memorial group — an organization focused on the history of political repressions and advocating for human rights.”

A hearing on the petition to revoke Memorial legal status has been set for Nov. 25, the group said. It wasn’t immediately clear whether it plans to continue working without being a legal entity like several other rights groups in Russia have done following earlier crackdowns.

In recent months, the Russian government has designated a number of independent media outlets, journalists and human rights groups as “foreign agents.” At least two disbanded to avoid a tougher crackdown.