Police are clashing on a downtown Moscow square with demonstrators trying to hold a second day of protests against alleged vote fraud in Russia's parliamentary elections.
Hundreds of police had blocked off Triumphal Square on Tuesday evening, then began chasing a demonstrators, seizing some and throwing them harshly into police vehicles.
The Interfax news agency reported that among the detained was Boris Nemtsov, a leader of the liberal opposition. Tuesday's rally followed a surprise Monday protest by thousands.
Prime Minister Vladimir Putin's United Russia party saw a significant drop in support in Sunday's election but it will still have a majority in parliament. Opponents say even that watered-down victory was due to massive vote fraud.