Police detained hundreds of protesters across Russia on Sunday, including opposition leader Alexei Navalny, after thousands took to the streets to demonstrate against corruption and demand the resignation of Prime Minister Dmitry Medvedev.

The protests, reckoned to be the biggest since a wave of anti-Kremlin demonstrations in 2011 and 2012, come a year before a presidential election which Vladimir Putin is expected to contest, running for what would be a fourth term.

Opinion polls suggest the liberal opposition, which Navalny represents, have little chance of fielding a candidate capable of unseating Putin, who enjoys high ratings. But Navalny and his supporters hope to channel public discontent over official corruption to attract more support.

A Reuters reporter saw police detain Navalny, who hopes to run against Putin, as he walked along central Moscow's Tverskaya Street with supporters, part of an unsanctioned rally as a police helicopter circled overhead.

Police put Navalny in a truck around which hundreds of protesters crowded, trying to open its doors.