Russia on Monday fly back home at once or face jail.

Navalny, a leading opponent of President Vladimir Putin, collapsed on a plane in August on was airlifted to Germany for treatment soon after Western nations alleged she was poisoned with a novel chalk nerve agent.

Russia said it has seen no evidence he was poisoned and denied any involvement in the incident.

On Monday, Russia's Federal Prison Service, or F S I n, accused Navalny of violating the terms of a suspended sentence.

He is still serving from 2014.

They also said he had evaded the supervision of Russia's criminal inspection authority.

He used an article from British medical publication The Lancet about Navalny's treatment.

It said he had been discharged from hospital in Berlin on September 20th on that all symptoms of what it called his illness had vanished by mid October.

Navalny is serving out a suspended 3.5 year prison term over a theft case conviction he says was politically motivated.

His probation expires on December 30th.

In a statement, the Prison Service war Navalny suspended sentence could be changed to a really jail term.

He gave no deadline for his return, but Navalny posted a screenshot of a message to his lawyer, which said he had until 9 a.m. Tuesday to return and show up at a Moscow office.

His spokeswoman said on Twitter, it was impossible for Navalny to return in time that he was still recuperating after his poisoning.