Navalny demands his clothes back from Russia, saying they are 'vital evidence'

Navalny is currently being treated at Berlin's Charite Hospital, after becoming gravely unwell on a flight from the Siberian city of Tomsk to Moscow a month ago.

Last week, Navalny's aides said they had taken items from his Tomsk hotel room to Germany, where a lab later found traces of a nerve agent on one of the water bottles he apparently drank from. Navalny's colleague who collected the items in Tomsk, chief investigator Georgy Alburov, previously told CNN the water bottle was not necessarily the object used to poison the Kremlin critic, suggesting the substance could have been placed on a different object.

In a statement released on Monday, Navalny said: "I'm interested in one thing now: my clothes. That is, the clothes I was wearing on the day of the poisoning, August 20. 30 days of 'pre-investigation check' were used to hide this vital piece of evidence.

"Before they allowed me to go to Germany, they took all my clothes off and I was sent there completely naked. Taking into account the fact that Novichok was found on my body, and a contact method of poisoning is very likely, my clothes are very important material evidence."

The German government has said the Kremlin critic was poisoned with a chemical agent from the Soviet-era Novichok group, a conclusion supported by two other labs in France and Sweden. The Kremlin has strongly denied any involvement but multiple questions remain.

At the weekend, Navalny said he was still unable to use his phone properly or pour himself a glass of water, but is on a "clear road" towards recovering from his near-fatal poisoning.

He posted a picture of himself walking down a staircase on Saturday, writing that he is regaining his physical and mental capacity.

Navalny's Monday statement comes a month after the suspected poisoning and was timed to coincide with the expiration date of a preliminary probe into the incident, which did not result in a criminal investigation.

Navalny's spokesperson Kira Yarmysh said in a statement on Monday that the Russian government had turned a blind eye to the incident.

"30 days is the maximum period of the 'pre-investigation check' and it can't be extended," Yarmysh said. "Therefore, we can now say the Russian government has officially decided to ignore Navalny's poisoning."

The Kremlin previously said it was seeking to launch a criminal probe into the matter. Russian authorities said poisoning was one version of what may have happened to the opposition leader, but it "wasn't confirmed, as no toxic substances were found in the patient's blood in Omsk and in laboratories in Moscow."