Leaders of European countries have criticized the arrest of Russian opposition leader Alexei Navalny and called on the Russian authorities to release him.

Alexei Navalny, who returned to Moscow late at night on January 17 after being poisoned with a nerve toxin and months of treatment in Germany, was arrested at the airport. He will spend the period before the trial in solitary confinement.

German Foreign Minister Heiko Maas said on Monday that Russia should release Alexei Navalny.

“After his convalescence, Alexei Navalny chose consciously and of his own free will to return to Russia because that"s where he feels his personal and political home is. That he was detained on his arrival by Russian authorities is utterly incomprehensible”.

European Council President Charles Michel lashed out at Russian authorities for detaining Navalny.

“The detainment of Alexey Navalny upon arrival in Moscow is unacceptable. I call on Russian authorities to immediately release him”, - twitted Michel.