An opposition leader says he and seven other activists were detained to prevent them from holding an anti-police rally in central Moscow.

Roman Dobrokhodov says police detained them as they gathered near the rally site. He spoke to The Associated Press by cell phone from a police station.

The Moscow police press office, however, denied anyone had been detained.

The detentions were reported by opposition Web site Kasparov.ru.

Police blocked off the square where the activists were to rally Sunday to demand an overhaul of Russia's notoriously corrupt police force. They also planned to give instructions on resisting arrest during protests.

Russian police often break up protests, which activists claim violates the constitutional right to assembly.