A spokesperson for Russian opposition leader Alexi Navalny said he has been hospitalized after being poisoned.

Kira Yarmysh posted on social media that the 44-year-old Navalny became ill as he was flying Thursday from the Siberian city of Tomsk to Moscow.  The plane made an emergency landing in Omsk and Navalny was rushed to a hospital.  She said he is unconscious and has been put on a ventilator.

Russia’s TASS news agency says Navalny is in serious condition, quoting the head doctor at the hospital.

"We assume Alexi was poisoned with something mixed with his tea,” Yarmysh wrote on her Twitter account.  "Doctors say the toxin was absorbed faster through the hot liquid.”

Yarmysh compared the suspected poisoning to an incident last year when he became ill while serving a brief jail sentence and was rushed to a hospital.  A doctor told his wife he suffered an acute allergic reaction that could have resulted from being poisoned with an unknown chemical.

Navalny is a fierce critic of President Vladimir Putin who has been arrested and jailed numerous times for organizing anti-government protests.  He has also founded a nonprofit foundation aimed at exposing government corruption. 

VOA