A 16-year-old boy is believed to be among those detained
Police say they have detained 29 opposition protesters in central Moscow on Sunday.
It comes a week after hundreds were arrested during a rally organised by leading Putin critic Alexei Navalny.
The city police's press service said today that "Twenty-nine people were detained by police for breaches of public order."
Among those detained was a 16-year-old boy called Pavel Dyatlov who became a symbol of youth protest in last week's rally when he was photographed climbing up a lamppost.
OVD Info, a website that monitors detentions of activists, say that at least 32 people had been detained including at least 4 minors.
One of Putin's leading critics Alexei Navalny is currently serving a 15-day sentence behind bars for disobeying police at last Sunday's event.
A spokeswoman for Navalny, Kira Yarmysh said that he had now idea about today's protest, saying on Twitter "He genuinely knows nothing about it. Unfortunately, communication is now severely hampered."
Last Sunday's protests were organised in cities all across Russia, most of which were not authorised by municipal officials.
The largest one in Moscow saw about 500 people detained according to police, while OVD-Info put the total at almost 1,000.