MOSCOW Russia's opposition said on Tuesday they feared Vladimir Putin had decided to use force to smother their protests after riot police detained hundreds of demonstrators challenging his presidential election victory.
After three months of peaceful anti-Putin protests, police hauled away more than 500 people, including opposition leaders, who attended unsanctioned protests in Moscow and St Petersburg on Monday or refused to leave after a rally that was permitted.
The police intervention sent a clear signal that Putin is losing patience with opponents demanding more democracy, openness and political reforms, and will crack down if they step out of line.
"Fear of his own people, the animal fear of losing power, and a reliance on the police baton - this is what we are seeing," Boris Nemtsov, a liberal opposition leader, wrote in a blog.
Novelist Boris Akunin, who has helped organize the protests, said he no longer believed the next rally - planned for Saturday - could pass off without trouble.
"It is absolutely clear that the period of peaceful rallies and marches is over. I see no need to organize any march on March 10 because it will lead to a clear display of aggression by the authorities," he said.
The police said they had acted in accordance with the law and Putin's spokesman, Dmitry Peskov, defended the intervention.
"The opposition action consisted of two parts, legal and illegal. In both cases, the police acted with the highest professionalism and acted legitimately and effectively, within the competence of the law," he said.
After four years as prime minister, Putin returned to the presidency after capturing almost 64 percent of the votes in Sunday's election. He was president from 2000 to 2008.
The restraint shown by many officers, even as they bundled protesters into vans, suggested that Putin is determined not to give his critics the chance to depict him as a dictator ready to suppress any challenge to his authority.
Witnesses said that although some protesters were hurt, and one said her arm had been broken, police seemed intent on avoiding casualties at the main protest on Moscow's Pushkin Square, often the scene of Soviet-era dissident protests.
But reporters said police used tougher tactics against a group who tried to protest at Lubyanka Square, in front of the headquarters of the Federal Security Service, successor to the Soviet-era KGB.
Protesters were also dragged roughly away in St Petersburg, Putin's home town.
Foreign investors are worried that clashes could break out between police and protesters, undermining the investment climate and denting prospects for reforms which they say are needed to reduce Russia's reliance on energy exports.
Russian stocks suffered their biggest daily fall in three months on Tuesday after ratings agency Fitch warned of the dangers of confrontation. Both the main dollar-based and rouble-traded stock indexes fell by more than 3 percent.
ALLEGATIONS OF FRAUD
The pattern appears clear: Putin will allow a few isolated protests, the place and time of which is agreed with the authorities, as a safety valve for disillusionment among mainly urban demonstrators with his 12-year domination of Russia.
He could also offer some conciliatory gestures to appease the opposition. In one such move, the Kremlin has ordered a review of 32 criminal cases including the jailing of former oil tycoon Mikhail Khodorkovsky and the refusal to register a liberal opposition group which has been barred from elections.
But Putin, a former KGB spy, will do his utmost to prevent what he regards as more radical protesters undermining his return to the Kremlin for a third term as president. Dissent will be dealt with forcefully.
"We saw fear in the eyes of the dictator. We saw weakness. We saw a man who is unsure of himself," Ilya Yashin, an opposition leader, told the rally at Pushkin Square after Putin shed a tear in his victory speech on Sunday.
"Has war begun? Why have they brought troops into the centre of our capital? Why the riot police? Who does he want to wage war with? Who is he protecting himself against?"
The U.S. ambassador to Russia, Michael McFaul, said on Twitter that the arrests were troubling and freedom of assembly and speech were universal values.
This earned him a rebuke from Russia's Foreign Ministry in a tweeted reply. It said the Russian police had shown far more restraint than U.S. officers clearing anti-capitalist protesters from sites in the United States.
The United States has called for an independent and credible investigation into all allegations of voting irregularities in the election. Several European countries have also signaled their concern over the allegations of cheating but at the same time underlined a desire to keep working with Russia.
International monitors said there had been some improvements from a parliamentary poll on December 4 which observers said was marred by irregularities, but the vote was still unfair and heavily skewed to favour Putin.
Russia's Foreign Ministry said the observers' report was balanced overall but it took issue with several criticisms, although it did not say what they were. Many Russians have lost hope of elections being fair and Putin introducing change.
"I used to love Putin, like any woman who likes a charismatic man. But now I think he is getting senile. Nobody can stay in power forever," Vasilisa Maslova, 35, who works in the fashion trade, said at Pushkin Square.
(Additional reporting by Lidia Kelly, Alissa de Carbonnel and Thomas Grove Editing by Douglas Busvine, Elizabeth Piper and Robert Woodward)