Who is Aleksei Navalny, Russia’s opposition leader who has been hospitalized after suspected poisoning?

Russia’s most high-profile opposition leader, Aleksei Navalny, is unconscious and on ventilator in intensive care on Thursday, Aug 20 after he consumed a cup of tea that is suspected to be poisoned.

Navalny was flying to Moscow from the Siberian city of Tomsk when he became ill midflight, prompting the plane to make an emergency landing 500 miles away in Omsk, near the border with Kazakhstan.

His spokesperson Kira Yarmysh wrote on social media, “We assume that Alexei was poisoned with something mixed into the tea. It was the only thing that he drank in the morning. Doctors say the toxin was absorbed faster through the hot liquid. Alexey is now unconscious”

Aleksei Navalny is a Russian politician and anti-corruption activist. He has organized demonstrations advocating reform against Putin and his political allies. Navalny has been arrested several times by Russian authorities.

According to a report by Slate, Navalny has been an outspoken critic of President Vladimir Putin, and this is not the first time that he has been hospitalized by being the victim of an apparent attack presumed to be carried out by Russia’s security services, which have been known to target dissidents in myriad macabre ways.

Earlier, he was hospitalized for what was technically classified a “severe allergic reaction” after being following an election protest to a ban on opposition candidates in Moscow’s City Council election.