Earlier in the day, activists who want the authorities to cancel the proposed rate increase — of between 17 to 22 percent — welcomed support from a celebrated Armenian-American musician, Serj Tankian, the leader of the band System of a Down.

Writing about the protest movement on Facebook, Mr. Tankian suggested that “monopolistic foreign-owned utility companies should be made a state asset and strictly regulated and audited by an independent panel.” He added that “Armenia’s civic society is burgeoning,” and noted that the protesters were perhaps inspired by previous campaigns of “peaceful civic disobedience against unjust programs,” like one over a proposed fare increase for public transportation.