Russian opposition leader Alexei Navalny hospitalized following suspected poisoning

Russian opposition leader Alexei Navalny is fighting for his life after falling ill on Thursday following a suspected poisoning. The outspoken critic of the Kremlin is in a coma  and on a ventilator at a hospital in Siberia.

Navalny's spokesperson said it is assumed that the 44-year-old was poisoned through a black tea he drank at the airport before takeoff on a flight returning to Moscow from the Siberian city of Tomsk. He started to feel unwell on the flight, which ultimately made an emergency landing in Omsk.

The deputy head physician of the hospital where Navalny is being treated told reporters Thursday that the medical team expects a formal diagnosis later in the day, but are considering poisoning as "one of the possible reasons for the deterioration of his state."

Kira Yarmysh, Navalny's spokesperson has been providing updates both via her Twitter feed and an appearance on Russian radio, where she said she was certain this was "an intentional poisoning."

The manager of the coffee shop where Navalny bought the tea told the press that he is "looking into all circumstances and studying [security camera] footage.”