"For the first time in history, the company has satisfied the illegal demands of Russian authorities and has taken down from YouTube the paid ads promoting the rally against pensions reform", said Leonid Volkov, a close partner of the opposition leader, on the social media.
Opposition leader Alexei Navalny - now serving a 30-day prison sentence for organizing unauthorized public events - called for the rallies, which were held in dozens of towns and cities to protest a government proposal to increase the state pension age by five years.
In Moscow the authorities rejected an application from Navalny's supporters to protest in the city centre, raising the possibility that the police may disperse the rally by detaining people, as they have often done in the past.
From 2019, the retirement age for men and women will start being increased gradually.More news: More than 1 million to flee as Florence rips toward East Coast
Speaking in the far eastern city of Vladivostok, Putin told government officials he was unfazed by the fact that re-runs would be needed in four regions.
Incumbent Moscow Mayor Sergei Sobyanin was re-elected with 70% of the vote, state-controlled news agency TASS reported.
United Russia also lost ground to the Communist Party and the nationalist Liberal Democratic Party of Russia (LDPR) in some areas in weekend elections to regional parliaments. But despite a huge get-out-the-vote campaign, turnout was just 30 percent as many Muscovites stayed away.
In 2013, Sobyanin barely escaped a second-round run-off after a strong challenge from Putin's top critic Alexei Navalny, who unexpectedly picked up over a quarter of the ballots.
Almost half of those detained were rounded up in St. Petersburg, according to the OVD-Info.More news: International Friendly Report: England v Switzerland 11 September 2018
"The state should have found the money it needed in the budget or through fighting corruption", 19-year-old Yegor Zhukov said at the St. Petersburg protest.
"My respect to those who took to the streets today, especially young people", said Roizman, who was briefly detained at the rally in Yekaterinburg.
Putin's spokesman Dmitry Peskov said police acted "in strict accordance with the law" adding that some were attacked by "hooligans and trouble-makers".
Observers noted fewer people turned up to protest against the reform than in May after Putin softened the pension reform.
The government's plan calls for the eligibility age for retirement pensions to be raised by five years, to 65 for men and 60 for women.More news: This may be our first look at OnePlus 6T in flesh