MOSCOW - Russian police arrested about 20 protesters on Wednesday night at a central Moscow square where demonstrators had moved after police uprooted them from a camp, the latest move in a broadening crackdown on the forces opposing President Vladimir Putin.
The detentions at Kudrinskaya Square come as the opposition tries to maintain momentum following a series of massive protests over the winter.
Several hundred demonstrators had gathered at the square outside one of the city's iconic Stalinist Gothic skyscrapers after an early morning police raid on activists who had set up a camp in a park in the centre of Chistoprudny Boulevard.
Video from the square streamed by Ekho Moskvy radio's website Wednesday night showed police forcing demonstrators into buses while other protesters yelled angrily. Hundreds of demonstrators remained on the square after the arrests
Police said about 20 people were detained. The state news agency RIA Novosti cited police as saying the detentions began when police were investigating food deliveries to the demonstrators and their attempt to set up a field kitchen. News reports also said prominent opposition figure Ilya Yashin was among those detained.
As they try to intimidate Putin's opponents, authorities have put leading protest organizers behind bars, threatened others with reprisals and proposed legislation introducing a 300-fold increase in the fine for taking part in unsanctioned rallies.
Some opposition leaders hope that the tough measures will foment anger and fuel bigger rallies. But others fear the repression will blunt the protest movement by scaring away many of the mostly middle-class protesters who turned out in the tens of thousands for peaceful demonstrations this winter.
A demonstration of at least 20,000 a day before Putin's May 7 inauguration turned into a fierce battle with police as some of the protest participants tried to march on the Kremlin. Scores were injured in clashes between stone- and bottle-throwing demonstrators and police who fought back with truncheons and tear gas. In the next few days police chased the opposition around city, rounding up hundreds on the streets and in cafes.
Then the crackdown eased, allowing the opposition to stage a camp on tree-lined Chistoprudny Boulevard, one of the most iconic and attractive places in central Moscow.
The organizers refrained from putting out political posters and chanting slogans so that the round-the-clock camp technically wouldn't count as an unsanctioned protest. The gathering daily attracted up to a few thousand during daytime, but attendance would drop to just a few dozen overnight.
The authorities let the camp go for a week, but lost patience after a court on Tuesday supported a lawsuit by local residents who claimed that the vigil was creating a mess. Police dispersed the camp early Wednesday and activists moved to Kudrinskaya Square, which fronts on the Garden Ring, one of the city's busiest thoroughfares.
Over the weekend, authorities also let a group of popular writers lead several thousand on a march across downtown Moscow unimpeded, and several top painters and other members of the capital's arts scene plan to stage a similar demonstration this week.
While authorities seem to show at least some tolerance to opposition action if the organizers fastidiously obey the law, they clearly aim to scare those in the opposition movement who appear eager to cross the barriers.
Popular blogger and anti-corruption lawyer Alexei Navalny and Left Front leader Sergei Udaltsov, the two leading organizers of the winter wave of protests, were sentenced to 15 days in jail for disobeying police following the May 6 rally that ended in clashes. Some Russian media reports speculated that they could face a longer prison term if accused of staging the violence.
The lawmakers who played a key role in protests, Ilya Ponomarev, Gennady Gudkov and Dmitry Gudkov, all members of the socialist Just Russia faction, have faced increasing pressure from the Kremlin party dominating the parliament.
On Tuesday, several members of the Kremlin party called for stripping the three of the immunity from prosecution they enjoyed as members of parliament.
"Go ahead, arrest deputies, put us behind bars, that will only speed up your demise," Gennady Gudkov, a KGB veteran turned fierce Putin critic, said during debates in the lower house. "Instead of political reforms, they want to only rely on force, but violence foments violence."
His son, Dmitry, tweeted Wednesday that the Kremlin party apparently is preparing to initiate a bill that would introduce a five-year prison term for organizers of the rallies that end in violence.
As part of the official pressure on the Gudkovs, a private security agency they own was targeted by authorities, who found some violations and ordered it stripped it of its arms.
In another move to tame the opposition, Putin's loyalists are also working on legislation that would raise the level of fines from the current maximum 5,000 rubles ($166) to 1,500,000 rubles ($50,000).
The rising official pressure comes as the opposition is desperately trying to maintain momentum amid the feelings of gloom that followed Putin's inauguration.
Some activists believe massive rallies are essential for shaking Putin's power, but others argue that the opposition must focus instead on grassroots activism and municipal elections, hoping they would help gradually make Russia a more open and pluralistic society.
Grigory Yavlinsky, the leader of the liberal Yabloko party, has warned the protest leaders against provoking police.
"If the organizers believe that the riot police cruelty will multiply the number of people eager to fight them, it's a wrong calculation," he wrote on his blog. "People will simply stop attending rallies and marches if blood is shed there, if they are beaten."
Associated Press writer Jim Heintz in Moscow contributed to this report.