Russian prosecutors have asked a Moscow court to label jailed Kremlin critic Aleksei Navalny’s anti-corruption organization and its regional offices as “extremist” organizations.

“Under the disguise of liberal slogans, these organizations are engaged in creating conditions for the destabilization of the social and socio-political situation,” the Moscow prosecutor’s office said in a statement on April 16.

It accused Russia’s largest opposition network of creating conditions for “changing the foundations of the constitutional order.”

The extremist label, if approved, would severely limit Navalny’s allies and activists from organizing, criminalizing such things as calling for or participating in protests. Navalny’s aides and organizations are already subject to frequent police raids and arrests over their political activities.

Navalny’s Anti-Corruption Foundation (FBK) exposes state corruption and his network of regional offices are located in dozens of cities.

The latest move against Navalny’s opposition movement comes as his aides are pushing for massive nationwide protests in the coming weeks.

Navalny was sentenced in February to 2 1/2 years in prison on charges he says were politically motivated. He was arrested in January after returning from Germany, where he was treated for the poison attack that European laboratories said involved a chemical nerve agent from the Novichok group.

His arrest in January triggered some of the largest nationwide protests in years and a harsh crackdown.

Navalny, 44, announced a hunger strike at the end of last month in protest at what he said was the refusal of prison authorities to allow him to receive proper medical care for acute back and leg pain.

With reporting by AFP, Current Time, and Reuters