Alexei Navalny is doing well according to the Russian authorities.
The opponent's health is "satisfactory," the prison services said on Thursday.
But his relatives say the opposite: the day before, they were worried about seeing his condition deteriorate since his arrival in a penal colony.
Alexeï Navalny himself claims to be "tortured" by sleep deprivation.
He indicates in a complaint to the Russian security services that his jailers deprive him of sleep, seeing it as a form of torture, according to the text of this letter published on his site.
The guards "deprive me of sleep, it is de facto a recourse to torture by sleep deprivation", he writes, explaining being woken up "eight times a night" by the men of the Russian penitentiary where he is held. .
According to his lawyer, he suffers from "severe pain" and fears "for his life and his health".
"On March 24, medical examinations were carried out at the request of the detainees," the service, the FSIN of the Vladimir region (north-east of Moscow) told Russian news agencies, adding that the state of health Alexeï Navalny was "considered stable and satisfactory".
READ ALSO>
Trial of Alexeï Navalny: "His courage gives him a moral posture that he did not have before"
Sentenced in February to two and a half years in prison in a fraud case dating from 2014, the most visible detractor of Vladimir Putin has been imprisoned since the beginning of March in a penal colony in Pokrov, 100 km from the Russian capital and famous for being very tough.
On Wednesday, his lawyer Olga Mikhailova said she did not have access to Alexei Navalny, adding that the 44-year-old opponent recently complained of "severe back pain" and began to no longer feel his legs but that he was not had only prescribed ibuprofen, a common anti-inflammatory drug.
Detention conditions comparable to "a concentration camp"
The anti-corruption activist survived last year poisoning with Novichok, an nerve agent developed in Soviet times, which had plunged him into a coma.
Morning essentials newsletter
A tour of the news to start the day
Subscribe to the newsletterAll newsletters
The substance has been identified by European laboratories, but Moscow has always rejected these conclusions which support the thesis of an assassination orchestrated by the Russian power.
VIDEO.
Pro-Navalny protests: more than 4,000 arrests across Russia
Returning to Russia in January after several months of convalescence in Germany, he was immediately arrested and convicted in a case that his supporters, NGOs and many international capitals see as politically motivated.
Since arriving in Pokrov, Mr. Navalny has described on social media his conditions of detention, claiming that his daily life as a prisoner is comparable to that of a Stormtrooper because of the rigid discipline in place and comparing it to a "camp of concentration ”.