Censor.NET reports citing OVD-Info.
"In total, OVD-Info is aware of 1,030 detainees at 51 local police stations," the message says.
On March 26, an unsanctioned anti-corruption rally took place in Moscow. The police report up to 8,000 people took part in the event. Its organizer, opposition politician Aleksei Navalny, was detained at the beginning of the rally.
Similar anti-corruption protests took place in many other cities across Russia. The police apprehended dozens of participants in unauthorized rallies in Vladivostok, Yuzhno-Sakhalinsk, Khabarovsk, Yekaterinburg and other cities.
The protests are said to have been triggered by Alexei Navalny's recent report exposing posh property of Russian Prime Minister Dmitry Medvedev.
According to official data by Russia's Interior Ministry, about 500 people have been detained.