Tens of thousands of Russians flooded Moscow's tree-lined boulevards today in the first massive protest against president Vladimir Putin's rule since his inauguration in May - a rally that came even as police interrogated key opposition leaders.
Since embarking on his third presidential term, Putin has taken a stern stance toward the opposition, including signing a repressive new bill last week introducing heavy penalties for taking part in unauthorised rallies.
Police on Monday searched opposition leaders' apartments, carting away computers, mobile phones and other personal items.
They also demanded that opposition leaders attend for questioning today just an hour before the rally began - widely seen as a crude attempt by the government to scare the protesters.
The march was being held on Russia Day, a national holiday that honours June 12, 1990, when Russian members of parliament decided that Russian laws should take priority over Soviet Union laws. The Soviet Union collapsed in 1991.
Left-wing politician Sergei Udaltsov snubbed the summons, saying he considered it his duty to lead the protest as one of its organisers.
Russia's Investigative Committee said it wouldn't immediately seek his arrest but would interrogate him later.
Anti-corruption blogger Alexei Navaly, liberal activist Ilya Yashin and TV host Ksenia Sobchak showed up for the interrogations, preventing them from attending the demonstration.
Investigative Committee spokesman Vladimir Markin said authorities had found a large amount of cash at Sobchak's apartment and would initiate a check to see whether she had paid her taxes.
Sobchak, the only daughter of St Petersburg's late mayor, a man who was Putin's mentor, had been spared reprisals until Monday's raid. "I never thought that we would slide back to such repressions," she tweeted Monday.
Braving a brief thunderstorm, protesters showed up on the landmark Pushkin Square ahead of the planned march and their numbers grew as they began marching down boulevards to a broad central avenue where a rally was being held. Despite fears following a violent police crackdown on a previous protest last month, the demonstration went on peacefully.
Speaking at the rally, Udaltsov reaffirmed a call for early presidential and parliamentary elections. He put the number of protesters at 100,000, while police estimated that about 20,000 showed up.
"Those in power should feel this pressure. We will protest by any means, whether peacefully or not," said Anton Maryasov, a 25-year-old postgraduate student. "If they ignore us, that would mean that bloodshed is inevitable."
Another protester, 20-year-old statistics student Anatoly Ivanyukov, said attempts by authorities to disrupt the rally would only fuel more protest. "It's like when you forbid children to do something, it makes them even more willing to do that," he said.
The police investigators' action follows the quick passage last week of a new bill that raises fines 150-fold on those who take part in unauthorised protests - fines that are nearly the average annual salary in Russia.
"I can't predict whether I'll leave here freely or in handcuffs," Yashin told reporters before entering the Investigative Committee headquarters for the interrogation. "The government is doing everything possible so that I don't end up there (at the protest)."
The top Twitter hashtag in Russia on Monday was "Welcome to the Year '37," a reference to the height of the purges under Soviet dictator Josef Stalin.
Tuesday's protest has city approval, but any shift from the agreed upon location and timeframe could give police a pretext for a crackdown.
Udaltsov urged protesters to march across town after the rally to the Investigative Committee's headquarters to demand the release of political prisoners - an action that would likely trigger a harsh police response. However, opposition leader Boris Nemtsov, speaking after him, said the demonstrators should act within the law.
"We must act in a responsible way, peacefully and calmly," he said.
Sergei Parkhomenko, a leading journalist who helped organise today's protest, said the authorities would like to see unrest to back their criticism of the opposition.
"They would be happy to stage some kind of provocation to prove that the people are just a herd of animals and the animals are always out of control," he said.
A big opposition rally a day before Putin's inauguration in May ended in fierce clashes between police and protesters, and some opposition activists said the violence was provoked by pro-Kremlin thugs.
The raids of the opposition leaders' homes and their questioning were connected to that May 6 protest.