YEREVAN, Armenia — About 500 people marched through the capital of Armenia on Monday to denounce visiting Russian President Vladimir Putin and to protest against plans to join a Moscow-led customs union.

Some of the crowd in central Yerevan held banners declaring "Putin, go home" or "No to the USSR," a reference to the Russian leader's efforts to bind former Soviet republics together more closely in economic and security alliances.

Putin flew to the South Caucasus country for talks on its decision in September to join the Customs Union with Russia, Belarus, and Kazakhstan, but began his visit in another city, Gyumri. He was due in Yerevan later on Monday.

The rally in Yerevan followed much larger protests in Ukraine, which suspended plans to sign a trade deal with the European Union (EU) last week and decided to rebuild economic ties with Russia instead.

Kremlin critics in the West accuse Putin of putting pressure on Ukraine, Armenia, and other former Soviet republics to reject agreements that would increase their integration with the EU.

Putin has made clear Moscow wants to increase its influence in the strategic region sandwiched between Russia, Turkey, Iran, and the oil and gas deposits of the Caspian Sea basin.

"We are going to strengthen our position in the South Caucasus, drawing on the best of what we have inherited from ancestors and good relations with all countries in the region," Putin told a Russian-Armenian regional forum in Gyumri.

"Participation in the Customs Union . . . already is bringing Russia, Kazakhstan and Belarus tangible dividends," he said.

Police blocked a central street as the demonstrators headed closer to the headquarters of President Serzh Sarksyan's administration, and protesters handed over a letter urging the government to renounce its decision to join the customs union.

Russia is the biggest foreign investor in Armenia and its largest trading partner. Bilateral trade grew 22 percent to $1.2 billion last year. Most trade has been imports to Armenia.

Three years ago Russia extended its lease on a military base in the landlocked, resource-poor nation of 3.2 million until 2044, ensuring it maintains a firm foothold in the South Caucasus.

The region also includes Azerbaijan, which has been embroiled in a territorial dispute with Armenia since the Soviet collapse, and Georgia, with which Russia fought a five-day war in 2008.