Russian opposition leader Alexei Navalny has been jailed for 15 days for resisting police orders during an anti-government protest.

Tens of thousands of people took to the streets in cities across Russia on Sunday in the biggest sign of defiance since protests in 2011 and 2012.

The protests come a year before Russia's presidential elections where Vladimir Putin is expected to stand for a fourth term.

More than a thousand people were detained along with Mr Navalny during the protest in Moscow, and hundreds more were held in cities across the country.

Mr Navalny was earlier fined 20,000 rubles ($350) for his role in organising the event.


Image: Russian President Vladimir Putin is expected to stand for a fourth term

The demonstrations took place after Mr Navalny repeated accusations of corruption against Russian Prime Minister Dmitry Medvedev.

Mr Medvedev's spokeswoman has called the allegations of corruption "propagandistic attacks".

She said the claims were pre-election posturing by Mr Navalny, who is hoping to stand against Mr Putin in next year's elections.

Last week the former lawyer was attacked by an unknown assailant and sprayed green as he opened a campaign office in the city of Barnaul.

Image: Last week he was sprayed green by an unknown attacker

The Kremlin condemned the protests, calling them a "provocation" and claiming minors were offered money if they were arrested while demonstrating.

"Essentially what we saw yesterday in several places, probably especially in Moscow, is a provocation and a lie," said Kremlin spokesman Dmitry Peskov.

The United States and the European Union both called on Russia to release the protesters detained on Sunday.

But Mr Peskov rejected the calls saying that the timing and location of events had to be agreed with the authorities in advance, something he said had not happened on Sunday.

He also promised that the Kremlin would listen to what people who took part in sanctioned anti-government protests in some Russian cities had to say.