Russian opposition leader Alexei Navalny is unconscious and placed on a ventilator in intensive care in hospital after falling ill from an apparent poisoning, his spokeswoman said Thursday.
Kira Yarmysh said Navalny was flying from Siberia to Moscow and his plane made an emergency landing after he fell ill.
Yarmysh told Echo of Moscow popular radio station: "I'm sure it was intentional poisoning."
"Alexei has toxic poisoning," she wrote on Twitter. "Alexei is now in intensive care."
Navalny is in the intensive care unit for toxicology patients in Omsk Emergency Hospital No. 1, the TASS state news agency confirmed.
"He is in a serious condition," the hospital's chief doctor Alexander Murakhovsky told TASS.
"Alexei is still unconscious. They have connected him up to a ventilator. They have called police to the hospital on our request," Yarmysh tweeted.
She wrote: "We think that Alexei was poisoned with something mixed in his tea. That was the only thing he drank in the morning."
"Doctors say the poison was quickly absorbed through the hot liquid," she added.
The 44-year-old, known for his anti-corruption campaigns against top officials and outspoken criticism of President Vladimir Putin, has suffered physical attacks in the past.
He endured chemical burns to his eye in 2017 when attackers threw green dye used as a disinfectant at his face outside his office.
In August last year Navalny suffered rashes and his face became swollen while he was in a police detention center serving a short term for calling for illegal protests.
Navalny's Foundation for Fighting Corruption has been exposing graft among government officials, including some at the highest level. Last month, the politician had to shut the foundation after a financially devastating lawsuit from Yevgeny Prigozhin, a businessman with close ties to the Kremlin.
