(Bloomberg) -- Russian prosecutors Monday ordered Alexey Navalny’s national network of campaign offices to suspend operations because of alleged “extremism,” deepening the crackdown on allies of the jailed opposition leader.

The order bans the groups from posting online, organizing events and using bank accounts pending a permanent court ruling, according to a copy posted in Twitter by Navalny’s allies.

The Moscow City Court Monday began considering prosecutors’ request to designate Navalny’s foundations as “extremist” and order them closed. Those proceedings are closed to the public as the authorities say materials involve classified information. Under Russian law, prosecutors don’t have the authority to suspend the funds’ operations, but the can ban the campaign offices, the court said.

The prosecutors’ order is the latest step in a steadily tightening squeeze on Navalny’s organization and allies.

‘Color Revolution’

An official “extremism” designation would effectively render all activity illegal, Navalny’s allies say. The Moscow campaign staff announced in Telegram that it would have to suspend all publications online after Monday’s order, with staffers continuing work in a personal capacity.

Authorities have alleged Navalny’s organizations were preparing a “color revolution” aimed at taking over the country on behalf of their western sponsors. Navalny and his allies deny that. The next session in the court case is set for Thursday.

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The nationwide network of campaign offices organized protests and challenged ruling-party candidates in regional and national elections, including a parliamentary contest set for September. Many local activists had been detained by authorities as they called for protests last week seeking for Navalny’s release. Tens of thousands of Russians turned out for those rallies around the country and more than 1,000 were detained by police.

Nerve-Agent Attack

His Anti-Corruption Fund had become known for its online exposes of alleged official corruption, including of a Black Sea palace allegedly used by President Vladimir Putin. The Kremlin denies that. Last summer, Navalny announced the Anti-Corruption Fund, already under legal pressure, was being replaced by the Foundation for the Defense of Citizens’ Rights.

The opposition leader was jailed when he returned to Russia in January after more than four months in Germany recovering from a nerve-agent poisoning he and western governments blame on the Kremlin. Russian authorities deny involvement.

On Friday, Navalny announced he was ending a three-week hunger strike he’d been conducting in prison to demand independent medical care.

The U.S. and its allies have warned Russia it could face consequences if Navalny were to die in prison.

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