Supporters of opposition leader Alexei Navalny are rallying across Russia demanding that authorities allow him to run for president.

The wave of rallies on Saturday, the 65th birthday of President Vladimir Putin, comes as Navalny is serving a 20-day jail term for calling for an unsanctioned protest. Heeding Navalny's call to support his bid, demonstrations were set to be held in nearly 80 Russian cities.

Navalny has declared his intention to run for president in the March 2018 election, even though a criminal conviction he calls politically motivated bars him from running. The 41-year old anti-corruption crusader has organized several waves of protests this year, casting a challenge to the Kremlin.

Putin hasn't yet declared his intention to seek re-election, but he's widely expected to run.