A protest against President Vladimir Putin has drawn tens of thousands of people determined to show opposition sentiment remains strong despite Kremlin efforts to muzzle dissent.
The demonstration, held in Moscow on Saturday, is the latest in a series of street rallies following a December parliamentary election won by Putin's party through what observers said was widespread fraud, and they grew in strength ahead of his effectively unopposed election in March to a third term.
"We have to defend the rights that we were deprived of, the right to have elections. We were deprived of honest elections and an honest government," said opposition activist Alexander Shcherbakov on Saturday.
"I've come to show that and to demonstrate that the people are opposed. I'm opposed to the illegitimate government and illegitimate elections."
Leftists, liberals and nationalists mixed with students, teachers, gay activists and others as they marched down the city's tree-lined boulevards chanting "Russia without Putin" and "We are the power here".
Many wore the white ribbons that have become the symbol of the protest movement.
About 7000 police officers stood guard along the route and a police helicopter hovered overhead.
A protest rally, held on a wide street named for the late Soviet dissident Andrei Sakharov, remained peaceful as it stretched into the evening.
As the 10pm deadline neared, a couple of hundred people were still on the street and police herded them towards a subway station.
One of the opposition leaders, Sergei Udaltsov, was detained along with a handful of his supporters when he tried to lead a group of about 50 on a new protest march.
Putin has shown less tolerance for the opposition since his inauguration in May.
New repressive laws have been passed to deter people from joining protests, and opposition leaders have been subject to searches and interrogations.
In August, a court handed down two-year prison sentences to three members of the punk band Pussy Riot for performing an anti-Putin song inside Moscow's main cathedral.
Big balloons painted with the band's trademark balaclava masks floated over the crowd on Saturday, while some rally participants wore T-shirts in support of Pussy Riot.
Many demonstrators targeted Putin with creative placards and outfits.
Some mocked Putin's recent publicity stunt in which he flew in a motorised hang glider to lead a flock of young Siberian white cranes in flight.
One protester donned a white outfit similar to the one worn by Putin on the flight with a sign reading: "Give up hope, each of you who follow me."
Another person held a placard that said: "We are not your cranes."