Russia's Interior Ministry wants to question opposition politician Aleksei Navalny in Berlin, where he is being treated after German doctors reported "unequivocal evidence" that he was poisoned with the military-grade nerve agent Novichok, contradicting their Russian counterparts who said they had found no trace of poison.

The ministry's transportation police directorate branch in Siberia said on September 11 that with Navalny coming out of a medically induced coma earlier this week, it is preparing a request that German authorities allow its investigators to take part in questioning the 44-year-old Kremlin critic and anti-corruption campaigner.

A German government spokesman said Berlin had yet to receive an official request from Moscow on the issue.

Separately, the public prosecutor's office in Berlin said it had been instructed by the state’s Justice Ministry to provide legal assistance to the Russian authorities and information on Navalny's health -- "subject to his consent."

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Navalny fell ill aboard a plane en route from the Siberian city of Tomsk to Moscow in late August and was hospitalized after the plane made an emergency landing in the city of Omsk.

He was then flown to the Charite clinic in Berlin, where German authorities said that "unequivocal evidence" indicated Navalny had been poisoned with the Soviet-era nerve agent, which the Kremlin has vehemently denied and Foreign Minister Sergei Lavrov called "groundless" on September 11.

Russian human rights defenders, opposition politicians and activists, and Navalny's relatives and associates, however, say the use of Novichok indicates that the Russian state only could be responsible for the poisoning.

Western politicians have said they also believe the poisoning was likely ordered by authorities in Russia and have urged Moscow to prove its lack of involvement.

The case has prompted international calls for Russia to carry out a transparent investigation or risk sanctions, but the country has not opened a criminal investigation, saying its medics did not find evidence of poison in tests.

U.S. Deputy Secretary of State Stephen Biegun told reporters on September 11: "It is unbelievable to us that this would happen on the territory of any country and the government would not react with urgency to investigate and hold accountable those who committed the crime."

In its statement, the Siberian transport police said they had been conducting "checks" into what happened and published some findings on Navalny's activities.

According to the statement, Navalny had snacks and drinks at the Xander Hotel, Velvet restaurant, and an apartment where he held meetings with his team members in Tomsk. He also stopped at the Vienna Coffeehouse at the Tomsk airport for a tea before boarding the plane.

The statement also says that five of Navalny's associates who were accompanying him in Tomsk have been questioned by police, while a sixth associate, Marina Pevchikh, who is a permanent resident of Britain, was not available for questioning.

Police are now working on tracking down other passengers who were aboard the plane, the statement said.

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The Kremlin says Berlin has not answered its request to see the medical data that led to the declaration that Navalny had been poisoned with Novichok.

However, doctors in Omsk said earlier that they had used an antidote to nerve agents while treating Navalny and that medical personnel in the Charite clinic also used it while treating the anti-corruption campaigner.

Germany’s Defense Ministry has said the data about Navalny has been provided to the Hague-based Organization for the Prohibition of Chemical Weapons.

Moscow's UN Ambassador Vasily Nebenzya on September 10 reiterated Moscow’s stance on the incident, saying that Russia "has no grounds to launch a probe" into the situation around Navalny.

"Our doctors -- who, by the way, saved Navalny -- did not find any trace of the chemical weapon in his tests. We have not received any evidence from Germany that would bring us to the conclusion that we are talking about a premeditated crime here," Nebenzya said.

With reporting by TASS, Interfax, AFP, dpa, AP, and RFE/RL's Russian Service