MOSCOW - Moscow police on Sunday arrested dozens protesting against military intervention in Ukraine after President Vladimir Putin won approval from senators to send in troops to the crisis-hit country.
Police said 40 people were detained for "attempts to violate public order" at a protest near the defence ministry in central Moscow, the Interfax news agency said.
Ovdinfo, a rights group that tracks arrests at demonstrations, put the number of detentions at 100.
Anti-war protesters also gathered at a separate demonstration on Manezhnaya square close to the Kremlin and Red Square, which police cordoned off and blocked with parked buses.
People held posters saying "No to war", while some also held Ukrainian flags and ribbons in the national colours of yellow and light blue.
Ovdinfo said about 30 people were detained.
Authorities have meanwhile agreed to allow a rally later Sunday in support of Putin's policy on intervention, even closing central boulevards to traffic to allow a march.
The pro-Kremlin United Russia party posted an invitation to the demonstration at 1300 GMT on its website, saying Russian speakers are "faced with persecution and violence because they speak Russian and are friendly toward Russia."
Russia's Federation Council, the upper house of parliament, on Saturday unanimously approved Putin's request to send Russian troops into Ukraine.
Lawmakers also said the Russian ambassador to the United States should be recalled.
Putin said Russia needs to protect the lives of Russian citizens in regions close to Russia and servicemen from its Black Sea fleet after a pro-Western opposition movement deposed Ukraine's President Viktor Yanukovych.
Kiev accused Russia of covertly invading the Crimean peninsula on Saturday, when armed men occupied several government buildings and the airport and installed checkpoints on the peninsula.