Thousands protest against Putin rule in Moscow

Russian riot police detained four opposition leaders and broke up a crowd of about 2,000 people who went ahead with a banned rally today to demand an end to Vladimir Putin's 13-year rule.

The opposition chose a symbolic location, in front of the Soviet KGB security police's former headquarters, for the rally marking a year of protests against Putin, and said the police intervention showed the limits on dissent under the president.

Police were out in force and helicopters buzzed overhead as protesters, wrapped in scarves and fur hats because of the extreme cold, chanted "Free political prisoners", "Down with the police state" and "Russia without Putin" on the vast Lubyanka Square in central Moscow.

One unfurled a banner saying "crooks and thieves" - the popular name used to describe the Russian leadership.

But the police eventually lost patience with the rally, which had been banned by Moscow city authorities, and strode across the square in helmets and flak jackets after about two hours, hauling protesters away one by one and locking elbows to push others away until no one was left.

About 40 people were detained, a police spokesman said, and there were minor scuffles.

Leftist leader Sergei Udaltsov and anti-corruption blogger Alexei Navalny were detained at the start of the rally and two fellow protest leaders, Ilya Yashin and Ksenia Sobchak, were detained on their way to the protest.

"I don't know how many people are here but I am proud of each and every one of those who came here. The main thing is that people are here, that they are expressing their view and showing that they exist," Navalny said before he was detained.

"Obviously the authorities don't like attempts to carry out such protest actions and the development of the protest movement in general. They don't like anything that threatens them."