Police in Moscow on Saturday began detaining supporters of jailed Kremlin critic Alexei Navalny after he called for demonstrations across the country against President Vladimir Putin's rule.

Navalny, 44, put out the call for nationwide protests after he was detained last week on arrival to Russia from Germany where he had been recuperating from a near-fatal attack with the Soviet-designed nerve agent Novichok.

In the centre of the capital, police detained several Navalny supporters ahead of the 2:00 pm (1100 GMT) official start of the rally, when protesters are expected to march towards the Kremlin, AFP reporters said.

Russian authorities ramped up pressure on Navalny's aides on the eve of the protests
Russian authorities ramped up pressure on Navalny's aides on the eve of the protests AFP / Kirill KUDRYAVTSEV

OVD-Info, a group that monitors political detentions, said more than 200 anti-Kremlin protesters had been swept up by law enforcement in around 30 cities across Russia.

Russian authorities ramped up pressure on Navalny's aides on the eve of the protests, handing short jail terms and fines to his close associates for violating protest legislation and urging people to take to the streets.

Russia's media watchdog had also issued a warning to social media platforms that hosted calls for a large turnout at Saturday's demonstrations.

Navalny's arrest sparked sharp condemnation from the leaders of Western countries who echoed calls from the Russian opposition for his release.