More than 4,500 held in Russia at protests against jailing of Kremlin critic Alexei Navalny

Navalny was arrested on January 17 after returning to Moscow from Germany where he had been recovering from a nerve agent poisoning in Russia last summer. He accuses President Vladimir Putin of ordering his murder, which the Kremlin denies. His dramatic return to Moscow despite the obvious threat of arrest and the second straight weekend of protests at his jailing pose a challenge for Putin.