March Against Executioners retraced the route to the downtown Bolotnaya Square, where 650 people were detained at after a similar rally on May 6, 2012 ended in violence.

Twelve protesters are on trial, and another 16 under investigation over last year’s clashes. Officials say the clashes were instigated by radical opposition leaders, while protest activists speak of police provocations.

City police said 6,600 showed up, while opposition leaders spoke of between 20,000 and 30,000. Last year’s rally attracted 8,000, according to police, or 50,000 to 100,000, according to various independent estimates.

Wednesday’s rally was joined by lawmaker Dmitry Gudkov, opposition politician Vladimir Ryzhkov, protest-minded writer and journalist Dmitry Bykov and whistleblowing lawyer Alexei Navalny, who recently announced plans to run for Moscow mayor in September.

Ten protesters were detained ahead of the rally’s start Wednesday for touting flags of the banned Left Front group, Ovd-Info.org human rights website. Left Front insignia raised no objections from police at previous opposition rallies in Moscow over the past 18 months.

Russian President Vladimir Putin said on Tuesday it is not right that the US State Department supports opposition activists in Russia.

“[Russia’s] diplomatic service doesn’t cooperate actively with the Occupy Wall Street activists, yet your diplomatic service actively cooperates [with Russia’s opposition] and supports them,” Putin said in the interview with Russia Today.

Putin said diplomatic services should mend ties between states and not get involved in domestic affairs. “I believe, this is wrong,” the Russian president said as he visited RT’s new Moscow broadcasting center.

Meanwhile, Putin said “any opposition is good, right and helpful” if it acts within the law. He added that if people are dissatisfied with the laws, the opposition should try to change them in a “democratic way.”

When protesters break the law, the government should use legal methods to “put everyone in the legislative field,” Putin said. “This is what's happening both in the United States and Russia,” he said. “But when we do that we are criticized, but when the United States does this, it is considered as a norm. These are the so-called double standards,” he added.

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No other incidents were reported at the event. Prosecutors also banned protesters ahead of the rally from carrying “cages” with photos of judges and investigators involved in the ongoing trial, opposition activist Ilya Yashin said on Twitter.