Russian opposition leader Alexei Navalny was on Saturday detained at an unsanctioned rally in central Moscow, two days ahead of Vladimir Putin's inauguration for a fourth Kremlin term, AFP reporters said.

Navalny had been warend by authorities not to organise unsanctioned rallies. Dozens of his supporters were detained during nationwide protests earlier Saturday, his team and an independent monitor said.

Navalny, who was barred from challenging Putin in the March presidential election, had called on Russians to stage a day of rallies across the country ahead of Putin's inauguration.