Alexei Navalny's Arrest Strain Ties Between Russia, West

Russian opposition leader Alexei Navalny's arrested 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.'

Navalny was detained at passport control at Moscow's Sheremetyevo airport after flying in Sunday evening from Berlin, where he was treated following the poisoning in August that he blames on the Kremlin.

Navalny's arrest adds another layer of tension to relations between Moscow and the West that have long been strained and were worsened by his poisoning.