More than 1,000 people were detained across Russia on Monday as part of the latest wave of anti-corruption protests.

According to figures from Russian police watchdog OVD-Info, 866 protesters were detained in Moscow June 12. At least 32 people were held overnight after attending the rally, which had not been sanctioned by the city government.

Hundreds were arrested in St. Petersburg during similar anti-corruption protests, OVD-Info reported. At least 245 people were still being held by police in St. Petersburg in the early hours of Tuesday morning, the watchdog said.

St. Petersburg’s Fontanka newspaper said 400 people in the city were facing prosecution for breaking local anti-protest laws, including 140 minors.

Arrests were also reported in other regional cities, the Far Eastern port of Vladivostok and the Siberian town of Novosibirsk.

Local police forces have disputed the figures, with officials reporting that only 150 people had been detained in Moscow and 500 in St. Petersburg, the Meduza news site reported.