Former world chess champion and opposition leader Garry Kasparov told an opposition rally in Moscow that the large police presence at the event shows that the Kremlin is afraid of peaceful protest.
As was the case two days earlier in St. Petersburg, the protest proceeded peacefully without police intervention, despite a massive show of force by security forces.
In April, police violently broke up the group's protests in Moscow and St. Petersburg.
Prior to the rally, however, police briefly detained -- and then released -- opposition activist Sergei Udaltsov, leader of the Red Youth Avant-Garde group. Udaltsov told RFE/RL police had been tracking him for several days.
"There has been a real hunt after me recently," he said. "The day before yesterday I was taken off a flight to St. Petersburg where I was flying to take part in the March of Dissent. I was under surveillance for three days. I had to use back streets to get around Moscow, trying to join the March of Dissent, but they still tracked me down and detained me."
Protesters gathered in a square in central Moscow, surrounded by metal barriers and rings of police. They chanted slogans, including "We need another Russia" and "Russia without Putin."
Pro-Kremlin groups unfurled a banner on a nearby rooftop labeling the demonstrators "paid prostitutes." A truck also repeatedly drove around the demonstrators playing laughter from loudspeakers.
Moscow authorities gave the opposition permission to hold the demonstration if attendance did not exceed 500 participants. Police took no measures against the protesters despite the larger crowd.
(with material from agency reports)