Russian prosecutors said on August 27 that they have no indication so far that a criminal act has been committed against Aleksei Navalny, and requested that German medics treating the opposition leader share his medical records.
The 44-year-old anti-corruption campaigner and staunch critic of President Vladimir Putin is currently in an induced coma in a German hospital after collapsing a week ago on a Russian commercial flight from the Siberian city of Tomsk, where he had been conducting his latest corruption investigation.
Earlier this week, doctors at the Berlin hospital where Navalny is being treated said their initial medical examination pointed to poisoning.
Russian doctors who had treated Navalny in a Siberian hospital have contradicted that diagnosis, while the Kremlin has claimed that German medics were "rushing" to use the word "poisoning."
Amid mounting Western calls for a transparent investigation into the case, the Russian Prosecutor-General's Office said that a preliminary inquiry launched last week had found "no evidence" of "deliberate criminal acts committed" against Navalny, and that it saw no basis to launch a criminal investigation.
German authorities have agreed to cooperate with Russia on the case, the office said, asking Germany to hand over "the evidence for the initial diagnoses they gave," including test results.
Meanwhile, the Siberian branch of the Interior Ministry's transportation unit said that it has been conducting a preliminary inquiry to "establish all the circumstances" surrounding Navalny’s illness and determine whether a criminal investigation should be launched.
Police said in a statement that they inspected locations that Navalny visited, his hotel room, and the routes he had taken in Tomsk, and examined security-camera footage.
They said no potent or narcotic substances were found.
In Moscow, Putin’s spokesman Dmitry Peskov said preliminary checks were always carried out in such situations and that there was no need for a formal investigation.
"Nothing has changed, we still don't have any understanding of what caused the state the sick man is now in," Peskov told journalists.
Navalny fell ill on a plane from Tomsk to Moscow on August 20. He spent two days in a clinic in Omsk, also in Siberia, before being transferred to the renowned Charite hospital in Berlin.
Doctors there said on August 24 that "clinical findings indicate intoxication by a substance from the group of active substances called cholinesterase inhibitors," adding that they do not yet know the specific substance involved.
Cholinesterase inhibitors are a broad range of chemicals that are found in several drugs as well as in some pesticides and nerve agents.
Russian doctors said their tests did not find any trace of poison while they treated Navalny.
His supporters say they think he was poisoned when he drank tea purchased at the Tomsk airport before boarding his flight, and accuse the Kremlin of being behind what they see as a deliberate poisoning.
Navalny’s team filed a request with Russia's Investigative Committee demanding that authorities launch a criminal investigation on charges of an attempt on the life of a public figure, but said they received no response.
Putin rejected "rushed and groundless accusations" when he discussed the case with Italian Prime Minister Giuseppe Conte on August 26, according to the Kremlin.
The Russian leader underscored Russia's "interest in a thorough and objective investigation of all the circumstances of the incident."
On August 27, French Foreign Minister Jean-Yves Le Drian said he did not understand why Russia did not opt for transparency, which would be "to their credit."
German Foreign Minister Heiko Maas once again urged Moscow to investigate Navalny's condition, saying: “If there is no investigation it will be not possible for Moscow to dismiss the accusations.”