Russian protesters on Thursday called for the release of activists they called political prisoners and urged the nation to unite against Vladimir Putin's crackdown on civil society.
About 1500 citizens and members of the motley opposition movement packed a central Moscow square to protest the detention of people arrested after clashes on the eve of Putin's inauguration to a third term in May.
A Moscow demonstration on 6 May erupted into street battles with riot police in some of the worst violence since unprecedented protests against Putin's decade-long rule first shook Russia late last year.
Investigators said earlier Thursday they had detained two more activists as part of their probe. Those detentions came on top of 14 activists already under investigation including 12 who have been arrested.
Thursday's rally grew into a show of support for other jailed activists including three members of all-girl punk band Pussy Riot who called for Putin's ouster in an unsanctioned Moscow cathedral performance in February.
Earlier this month the three women were ordered to stay in pre-trial detention until January. They could face up to seven years in prison.
Opposition activists told Thursday's rally the authorities sought to intimidate society into silence and called on Russians to fight back.
"They declared a war on us!" leftist leader Sergei Udaltsov said.
Mark Feigin, one of the Pussy Riot defence lawyers, called on those gathered to attend mass rallies scheduled for September and October when more protests are expected after a relative lull in summer.
"To their rejection of law there is a response of the street," he said.
Activists accuse the Kremlin of a ruthless crackdown on the nascent opposition movement since Putin's return for a historic third term.
An AFP correspondent estimated the turnout Thursday at around 1500. Police said 800 people had turned up, including 150 journalists and bloggers, and they said they had detained one man.
The crowd chanted "Russia without Putin" while slogans read "They are behind bars so that you live in fear" and "Down with the Inquisition".
Several activists recited poems from the stage in a move reminiscent of a Soviet-era tradition that saw dissidents gather in central Moscow to read poetry under the watchful eye of the KGB security service.
Rights activist Yury Dzhibladze said Russia was increasingly looking like neighbouring Belarus whose government has been the subject of Western sanctions due to clampdowns on the opposition.
"The situations in our countries are quickly becoming alike," said Dzhibladze, holding a placard reading "Solidarity is stronger than repression".
Some at the rally expressed doubt that the authorities would take notice of the protesters' demands.
"Those who make decisions do not give a damn about this crowd," Mikhail Kavun, a geologist, told AFP. "I am here to express moral support."
As part of the probe into the 6 May violence, police last month raided the homes of prominent opposition leaders including Udaltsov, anti-corruption blogger Alexei Navalny and TV host Ksenia Sobchak, who is the daughter of Putin's late mentor and former Saint Petersburg mayor Anatoly Sobchak.
Around €1.5-million ($1.8-million) have been seized from Sobchak as part of the investigation into the violence. A Moscow court earlier Thursday dismissed her request to have the money returned.