Video appears to show emergency workers rushing on a plane to take Putin opponent Alexei Navalny to the hospital after a suspected poisoning

• A video appears to show a team of medics rushing on a plane to help Alexei Navalny, a prominent critic of Russian President Vladimir Putin, after a suspected poisoning.
• Navalny's spokeswoman Kira Yarmish tweeted that the Kremlin critic fell ill on a flight on Thursday. "We assume that Alexei was poisoned with something mixed into his tea," she said.
• A video posted to Instagram Stories by a fellow passenger under the name DJ Pavlin shows staff rushing up and down the aisle, while a loud, pained groan is heard throughout the cabin.
• "At the start of the flight he went to the toilet and he didn't come back. He became very ill and they could barely resuscitate him as he screamed in pain," DJ Pavlin wrote.
• Navalny is currently in a coma and in grave condition at a hospital in Omsk, Yarmish said.

A video appears to show the moment emergency workers on a plane rushed to help prominent Kremlin critic Alexei Navalny after a suspected poisoning attempt.

On Thursday morning, Navalny's spokeswoman Kira Yarmish tweeted that he had fallen ill during a flight from Tomsk, Siberia, to Moscow.

Yarmish said the plane made an emergency landing in Omsk, a city between Tomsk and Moscow, and Navalny was taken to the hospital.

"We assume that Alexei was poisoned with something mixed into his tea. That was the only thing he drank this morning," Yarmish said.

A video shared widely on social media — first posted to Instagram Stories by a passenger onboard the same flight named DJ Pavlin — appears to show medics attending to Navalny.

As medical staff rush up and down, a loud groan of pain can be heard from the front of the plane.

In a second Instagram story, medical equipment can be seen blocking the aisle.

Along with the video, DJ Pavlin posted a message to his Instagram story saying: "At the start of the flight he [Navalny] went to the toilet and he didn't come back."

"He became very ill and they could barely resuscitate him as he screamed in pain. They are not saying what is wrong with him. Now we have landed in Omsk. An ambulance came."

Earlier, DJ Pavlin had posted a photo of what appeared to be Navalny sitting in a cafe in the airport.

Navalny is currently in a coma in the intensive care ward of a hospital in Omsk, Yarmish tweeted, adding that there was a heavy police presence.

"The intensive care unit is full of police officers. They try to get an explanation from the doctor. The doctor saw me in the distance in the corridor, said that 'some things are confidential' and took the police to another room," she wrote.

A Russian law-enforcement source told the state-run Tass news agency that Navalny may have ingested a poison by himself. Yarmish called the report "state propaganda."

Navalny has been President Vladimir Putin's chief critic for more than a decade.

He has been regularly imprisoned for protesting the regime, and survived a poisoning attempt in July 2019 while in prison.