Kremlin critic Navalny seen walking in photo from hospital - Navalny's Instagram

Russian opposition politician Alexei Navalny posted a picture on Instagram of himself walking down stairs and said that his path to recovery was "clear, although long".

He said he still has difficulties climbing stairs because his legs tremble.

Navalny, the leading opponent of Russian President Vladimir Putin, fell ill in Siberia last month and was airlifted to Berlin. Germany says laboratory tests in three countries have determined he was poisoned with a Novichok nerve agent, and Western governments have demanded an explanation from Russia.