Navalny's personal doctor not allowed to see him

Alexey Navalny's personal doctor and ally Anastasia Vasilyeva on Thursday said she wasn't allowed see the Russian opposition leader at a hospital in Omsk.

Navalny is in a coma and on a ventilator in a hospital intensive care unit in Siberia after falling ill from suspected poisoning during a flight on Thursday morning.

Vasilyeva told reporters outside the hospital that she had not been given anymore information about

Navalny's condition beyond what was released to the public.

The 44-year-old critic of Russian President Vladimir Putin felt unwell on a flight back to Moscow from Tomsk, a city in Siberia, and was taken to a hospital after the plane made an emergency landing in Omsk, Navalny's spokeswoman, Kira Yarmysh, said on Twitter.

Navalny's wife Yulia also went to the hospital in the afternoon, but medical workers would not let her see her husband because she did not have their marriage certificate and the patient did not consent, according to Yarmysh.

Doctors at the hospital remain tight-lipped about Navalny's diagnosis and only said they were considering a variety of theories, including poisoning.