New Delhi: Russia's most prominent opposition politician and President Vladimir Putin’s critic, Alexei Navalny, is suffering from severe stomach pain inside jail that could be an act of slow poisoning, news agency Reuters quoted his spokesperson as saying. "He doesn’t eat anything because he is prohibited from receiving parcels with food or to buy food in the prison store and the food that is provided by the prison to him actually worsens his stomach pain," his spokesperson Kira Yarmysh said.


According to the report, an ambulance was called for Navalny to the maximum security IK-6 penal colony at Melekhovo, where he is currently lodged.


“His health is not in a good condition. We can't rule out the idea that he is being poisoned, not in a huge dosage as before, but in small ones so that he doesn't die immediately but for him to suffer and to ruin his health,” Yarmysh told Reuters.


Yarmysh further said that although there was no definitive proof of the poisoning theory, that he had never had such stomach pains before hints at it.


She said that medicine sent to Navalny's prison by his mother are not being collected by prison officials from the post office and was returned.


"He is in total isolation and we do not know what is happening to him. I am actually terrified because no one knows what is happening,” Yarmysh said.


Navalny, who is serving combined sentences of 11-1/2 years on charges of fraud and contempt of court, that he claims were an attempt to silence him, said on Twitter on Tuesday that he had been moved back into solitary confinement and forced to endure "extremely hellish" conditions.


Meanwhile, when asked about claims that Navalny might have been slowly poisoned, the Kremlin said it was not following his health status and that it was a matter for the federal penitentiary service.


It is to be noted that Navalny is a former lawyer who rose to prominence more than a decade back after he criticised President Vladimir Putin and the Russian government over alleged corruption.