BERLIN (Reuters) - Anti-Kremlin activist Pyotr Verzilov would probably have died following an apparent poisoning in Moscow last week if he had not received prompt medical treatment, his doctors in Germany said on Tuesday.

Verzilov, publisher of a Russian online news portal with close ties to the outspoken activist group Pussy Riot, is still very disoriented as he convalesces in Berlin’s Charite hospital following what his ex-wife said was either an assassination attempt or a warning shot.

Doctors at the hospital said Verzilov was suffering from anti-cholinergic syndrome, a condition in which the passage of certain neurotransmitters is blocked, the sudden onset of which was strongly indicative of poisoning.

“I don’t believe his position was seriously life-threatening in hospital, but we can imagine an unfavorable outcome if he’d been alone at home,” Kai-Uwe Eckardt, the doctor treating him in Berlin, said.

Verzilov, known in Russia for protest stunts including a pitch invasion at the World Cup final, was treated in a Russian hospital for four days last week before being flown to Berlin for further care.

Activists and security services are on high alert for poison attacks with origins in Russia following the poisoning of former Russian double agent Sergei Skripal in Britain earlier this year, blamed by London on Moscow.

Jaka Bizilj, a Germany-based activist who helped arrange Verzilov’s treatment there, said Verzilov had not stopped hallucinating his cat Rubinstein in the hospital room, and had taken one of his Berlin doctors for a prison warden. “But he’s getting better every day.”

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At a press conference given by Verzilov’s mother, his partner and his former wife, Pussy Riot founder Nadezhda Tolokonnikova, Tolokonnikova said Verzilov might have been targeted by law enforcement agencies embarrassed by his stunts.

“Probably it was an assassination attempt and if not it was intimidation,” she told journalists on Tuesday, adding that she thought the Canadian-Russian dual citizen would return to Russia after an expected full recovery.

“No one who is taking part in political activities in Russia right now can really be safe,” added Tolokonnikova, who herself became a worldwide figure of dissent when she and two bandmates were jailed for performing a song critical of President Vladimir Putin in a Moscow cathedral.

She credits her then-husband for keeping the case in the international spotlight while she was imprisoned from 2012-2013. They later divorced but have remained close.

Verzilov was taken ill on Sept. 11 after accompanying his partner Veronica Nikulshina to a court hearing in Moscow. She described taking him to hospital after finding him unwell, pupils widely dilated, after he had taken to bed.

Doctors at the Charite hospital said the rapid onset of symptoms - including high blood pressure and dry mucous membranes - strongly indicated poisoning, but it was almost impossible to identify what poison had been used so long after it was administered.

Verzilov was no longer in danger but still needed intensive medical care, the doctors said. His care was being paid for by his Canadian medical insurance.