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 on Saturday 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 cold, chanted "Down with the police state" and "Russia without Putin" on the Lubyanka Square in central Moscow.
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.
All four were released without charge hours later, indicating they had been detained to prevent them stirring up the crowd at the protest.
Protests began a year ago after Putin's United Russia party won a parliamentary election marred by allegations of vote-rigging, but quickly developed into the biggest movement against the former KGB spy since he first came to power in 2000. At their peak last winter the biggest rallies attracted up to 100,000 people, witnesses said.