MOSCOW, Feb 1, 2024 (BSS/AFP) - Jailed Russian opposition leader Alexei Navalny called on Thursday for Russians to protest against Vladimir Putin during next month's presidential election.

Putin is set to be re-elected for another six-year Kremlin term in a tightly controlled poll set for 15-17 March.

In a post published on social media by his team Thursday, Navalny called for his backers to head to the ballot box at the same time on election day, forming queues to show their opposition to the Kremlin boss.

"This could be a powerful demonstration of the mood of the country ... real people queueing up to vote against Putin," he wrote.

Navalny is being held in a remote Arctic prison, serving a 19-year sentence on charges lambasted by him, rights groups and Western governments as political retribution for opposing Putin.

Protests against the regime are effectively illegal in Russia.

Navalny urged his supporters to head to polling stations at 12 noon on the main day of voting -- Sunday 17 March -- as a form of legal protest that the authorities would not be able to stop.

"It will be a real nationwide protest, that will take place not just in every city, but in every neighbourhood of every city," he said.

"It is perfectly legal and safe ... it is completely impossible to prevent it," he added.

He has called for people to vote for any candidate except Putin in the contest.

His wife and some of his associates in exile have backed surprise pro-peace campaigner Boris Nadezhdin.

The Kremlin has repeatedly said Russian society is united behind Putin.

Critics say decades of censorship, strict anti-dissent laws and the jailing of Kremlin critics are covering up a groundswell of opposition to him.

Putin will have been in power for more than three decades as either president or prime minister at the end of his next six-year term.

Navalny was arrested in 2021 when he returned to Russia after receiving medical treatment in Germany for what medical tests showed was a nerve agent poisoning.

He had fallen ill while campaigning in Siberia in 2020 ahead of Russian local elections. In a subsequent investigation, his team named a Kremlin assassination squad it said carried out the attack.