moscow kremlin critic alexei navalny call supporters wednesday hold street protest weekend across russia defiance official ban demand navalny allow run next year presidential election navalny vocal critic president vladimir putin jail 20 days monday repeatedly violate laws govern organization public meet rally arrest third year mean miss campaign rally plan putin hometown st petersburg oct. russian leader birthday appeal supporters via facebook page navalny call attend protest st petersburg moscow saturday add 80 support group meanwhile organize protest across russia task make oct. day every decent person pronounce aloud least two demand political competition navalny admission poll say appeal say dictate jail authorities ban plan weekend rally moscow st petersburg kremlin warn tuesday call protest would prosecute putin say early wednesday yet decide whether would run re-election march 2018 something widely expect opinion poll show putin navalny run incumbent would win wide margin jail kremlin critic call russians protest putin 's birthday