Armenia's increased interest in closer ties with the EU is due, among other things, to its conflict with Azerbaijan over territory and a growing distance from the regime in Moscow.
Belarus, Kyrgyzstan and Kazakhstan also stand behind the Russian demands for a referendum.
"Prime Minister Nikol Pashinyan himself has said that he is considering a referendum on the question of how Armenia should behave: join the Eurasian Union or the European Union. We want it to happen as soon as possible," Putin said at a press conference in Astana, Kazakhstan.
