Alexei Navalny, Putin's arch-rival and critic, has been discharged from hospital in Germany after recovering from a failed Novichok poisoning.
Doctors at Charite hospital in Berlin say the politician's health 'has improved to such an extent that acute medical care could be ended' after 32 days in their care.
Medics said they 'consider a full recovery possible' given Navalny's current condition, but cautioned that long-term effects of the poison may take a while to become apparent.
Navalny has vowed - via his spokeswoman - to return to Russia to continue his opposition to Putin, though exactly when this will happen is unclear.
Alexei Navalny has been discharged from hospital in Germany after recovering from a failed Novichok poisoning (pictured, Navalny in hospital yesterday with what appear to be scars on his neck, similar to those received by Yulia Skripal after she was also poisoned with Novichok)
The news comes just over a month after Navalny fell ill after boarding a flight at Tomsk airport in Russia (pictured left) and had to be rushed off the plane in a coma (right)
Just hours before the news broke, Navalny uploaded a photo of himself in hospital to Instagram, revealing several prominent scars on his neck.
One, at the base of his windpipe, appeared similar to the tracheotomy scar seen on Yulia Skripal - another vicitim of Novichok - as she appeared in public for the first time after being poisoned.
A tracheotomy is a small incision that is used to insert a breathing tube into a patient's lungs when they have lost the ability to breathe for themselves.
Alongside the photo, Navalny posted a message mocking Putin and his suggestion - made in a phone call with Emmanuel Macron - that Navalny could have swallowed the Novichok himself.
'Putin told his French counterpart: "Navalny might have swallowed this poison himself." A good theory. I believe it deserves a most thorough examination.
'I brewed Novichok in the kitchen. Sipped it quietly from a flask while on board the plane. Slipped into a coma.
'Before that, I agreed with my wife, friends and colleagues that if the Health Ministry insisted on me being taken for treatment to Germany, they should not agree to it under any circumstances.
'The final aim of my devious plan was to die in an Omsk hospital and end up in an Omsk mortuary. But Putin has outsmarted me.
'He is nobody's fool. As a result, I, like a fool, spent 18 days in a coma but failed to achieve what I wanted. The provocation has failed.'
The news that Navalny has been released comes five days after he last shared an update on his condition, which showed he could stand and walk.
Pictured standing on a hospital stairwell, the 44-year-old revealed that he had initially been unable to read or write after waking from an 18-day coma that he fell into after being poisoned on a plane in Russia on August 20.
'Until quite recently,' he wrote, 'I did not recognise people and did not understand how to talk.'
It is not clear where Navalny will stay until his eventual return to Russia.
The Kremlin continues to deny involvement in the poison plot, and has requested evidence from Germany to support its conclusion of Novichok poisoning.
Russia has also asked to send agents to interview Navalny, despite NATO warnings that the state 'will try again' to kill him.
Russian opposition leader Alexei Navalny poses with his wife Yulia and their children at the German hospital where he is being treated after being poisoned with Novichok
Navalny arrives at Berlin's Tegel Airport after he was airlifted from Russia. Doctors at the German hospital say his condition has been improving
NATO chief insist Russia was behind the poisoning, saying there is 'no other explanation', while France and Sweden have also concluded that Novichok - a Russian-made nerve agent - was used in the attack.
It was initially suggested by Navalny's friends that he was poisoned with a cup of tea that he drank at Tomsk airport shortly before boarding the flight where he fell ill.
But his political allies now believe the agent was slipped into a water bottle he drank from at a hotel.
After Navalny fell ill, the aircraft made an emergency landing in Omsk and he was initially taken to hospital in the Siberian city.
The following weekend he was airlifted to Berlin, where doctors at the Charite hospital treated him with the antidote atropine and kept him in a medically induced coma.