Jailed Vladimir Putin critic Alexei Navalny says he has been transferred permanently to a 'dog pen' isolation cell.
Since mid-August, the Russian opposition activist has spent 67 days in isolation at the IK-6 security prison where he is being held in the Vladimir region, east of Moscow.
Stints in the small cramped cell, which he calls a "punishment cell", are usually limited to 15 days, but now he fears this time it is permanent.
