Russian opposition figure Alexei Navalny is in a Coma from suspected poisoning, his spokeswoman has said.
The anti-corruption campaigner was reported to have fallen ill while on the plane necessitating an emergency landing at Omsk where he was rushed to the hospital and is currently unconscious.
His accompanying team suspects he was poisoned through the tea he was served on the plane.
Mr Alexei Navalny , 44, has for years been among President Vladimir Putin’s harshest critics.
In June he described a vote on constitutional reforms as a “coup” and a “violation of the constitution”. The reforms allow Mr Putin to serve another two terms in office, after the four terms he has already had.
Mrs Kira Yarmysh, his spokeswoman who is also the press secretary of the anti corruption foundation tweeted “
“This morning Alexei Navalny was returning to Moscow from Tomsk.
“During the flight, he felt ill. The plane made an urgent landing in Omsk. Alexei has toxic poisoning.”
She added: “We suspect that Alexei was poisoned by something mixed into [his] tea. It was the only thing he drank since morning.
“Doctors are saying that the toxic agent absorbed faster through the hot liquid. Right now Alexei is unconscious.”
