Top Kremlin critic Alexei Navalny dies in prison

The Kremlin's most prominent critic Alexei Navalny has died in an Arctic prison, say Russian authorities, announcing his death a month before an election poised to extend Vladimir Putin's hold on power.

Navalny's death after three years in detention and a poisoning which he blamed on the Kremlin deprives Russia's opposition of its figurehead at time of intense repression and Moscow's campaign in Ukraine.