Russian opposition leader Alexei Navalny’s arrest as he arrived in Moscow after recovering from his poisoning with a nerve agent drew criticism from Western nations and calls for his release, with Germany’s foreign minister on Monday calling it “incomprehensible.”

Russian opposition leader Alexei Navalny was arrested Sunday at a Moscow airport as he tried to enter the country from Germany, where he had spent five months recovering from nerve agent poisoning that he blames on the Kremlin.