MOSCOW (AP) — Supporters of jailed Russian opposition leader Alexei Navalny are calling for a new massive protest across the country to demand his release. In a statement posted Tuesday on Navalny’s website, they urged Russians to sign up for a protest on an interactive map and said they will set a date for it when the number of people willing to take part reaches at least 500,000 nationwide. The organizers claimed in a statement that the rally would the biggest that Russia has seen. The 44-year-old Navalny, who is Russian President Vladimir Putin’s most outspoken opponent, was arrested on Jan. 17 upon his return from Germany, where he spent five months recovering from a nerve-agent poisoning that he blames on the Kremlin.