Russian opposition politician Alexei Navalny was seen walking down the stairs in a photo posted on his Instagram feed on Saturday, five days after a Berlin hospital said he had been taken off a ventilator and could breathe independently. Mr Navalny, the leading opponent of Russian President Vladimir Putin, fell ill on a domestic flight in Siberia last month and was airlifted to Berlin by an NGO while still in a coma. "Let me tell you how my recovery is going. It is already a clear path although a long one," he wrote. In the Instagram post he said he had difficulties using his phone, pouring water or climbing stairs because his hands failed him and his legs trembled. Mr Navalny said in his post that after weeks in a medically induced coma and with assisted breathing, his current health problems seemed minor. "I'll tell you why. Only recently I couldn't recognise people and didn't know how to talk," he wrote. Germany says laboratory tests in three countries have determined that Mr Navalny was poisoned with a Novichok nerve agent, the same substance Britain accused Russia of using to poison former double agent Sergei Skripal in March 2018. Western governments have demanded an explanation from Russia for poisoning of Mr Navalny. The Kremlin denied Russia was responsible for the politician’s illness and said that there was not enough evidence of his poisoning. Russian authorities have refused to open a formal probe into Mr Navalny's case and instead have launched a preliminary procedure, which should conclude if an investigation is needed. Russian prosecutors also ordered an inspection of the hotel in Siberian city Tomsk where Mr Navalny stayed before collapsing on a plane and where his team said traces of Novichok were discovered on a water bottle. The inspection found several minor health and sanitation violations in the hotel's restaurant, for which its staff would be fined 62,000 roubles (Dh3,011), according to a report on the Prosecutor's General Office website, published on Saturday. The head of Germany's foreign affairs committee, Norbert Roettgen, told the Frankfurter Allgemeine Sonntagszeitung weekly newspaper that there should be an international investigation into how the Kremlin critic fell ill. "This can be done within the framework of the UN or the Council of Europe," he said. Earlier this week, Mr Navalny posted his first picture from hospital, surrounded by his family. His spokeswoman said he planned to return to Russia as soon as he recovers.