The US department of state has strongly condemned the detention of hundreds of protesters throughout Russia, including the country's opposition leader, on Sunday.

Thousands took part to anti-corruption protests swept across 80 Russian towns and cities in what are believed to be the biggest demonstrations in the country since 2012, with the largest held in Moscow and St Petersburg.

Alexei Navalny, a campaigner who hopes to stand against Vladimir Putin in next year's elections, was bundled into a police van on Sunday morning as he approached a group of protesters in Moscow's Pushkin Square.