Moscow (CNN) A member of Russian protest group Pussy Riot has arrived in Berlin for medical treatment, following what the activists claim was a suspected poisoning in Moscow last week.

Pyotr Verzilov, who is also the husband of prominent band member Nadezhda Tolokonnikova, flew into Berlin on Saturday, according to Germany's Cinema for Peace Foundation, a non-profit humanitarian group that has previously advocated for Pussy Riot and which organized the flight.

Verzilov had been in the intensive care unit at a Moscow hospital after falling ill. His father and wife "pushed for the immediate move to Berlin in order to find out if he was poisoned and by what, and to ensure the best recovery," said Jaka Bizilj, founder of the Cinema For Peace initiative and chairman of the board of the foundation.

The activist's wife, better known as Nadya, on Saturday posted a photo on Twitter of her visitor badge at Berlin Brandenburg Airport, saying he would soon be arriving. Another video appeared to show Verzilov on a plane.

The Russian punk band -- known for obscuring their identities with colorful balaclava-style masks -- is an outspoken critic of the Putin government. Russian foreign ministry spokeswoman Maria Zakharova had no comment on Verzilov's illness, when contacted by CNN.

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