A group that monitors police actions and political repression in Russia says at least 12 people have been detained in Russia's fourth-largest city while protesting plans to start construction of a cathedral in a city park.
Hundreds of people turned out in Yekaterinburg for the second consecutive day of demonstrations against the cathedral.
Opponents say the building would take away green and recreational spaces needed by residents of a city with 1.5 million people.
The OVD-Info organization that reported Tuesday's arrests said the detained demonstrators were taken to police stations. It was not immediately clear if charges would be filed.
Yekaterinburg is about 1400 kilometers (880 miles) east of Moscow.