Hundreds of people have marched through the Armenian capital Yerevan to denounce the visit of Russian President Vladimir Putin.
It follows Armenia’s decision in September to pull out of an association agreement with the EU and instead to join a Moscow-led customs union.
Police blocked a street as demonstrators tried to reach the headquarters of President Serzh Sarksyan’s administration.
The protesters are strongly opposed to the Russian leader’s efforts to bind former Soviet republics together more closely.
Scuffles broke out between protesters and police. Armenian media reports said about 100 people were arrested.
Away from the disturbances, a letter was handed over urging the government to change its mind.
Putin began his visit to the South Caucasus country in another Armenian city; he was due to head to Yerevan later for talks.
Critics of the Kremlin have accused Putin of putting pressure on former Soviet republics including Armenia and Ukraine, to reject deals that would lead to greater integration with the European Union.
The Russian president wants to increase Moscow’s influence in the strategically important region.