They were arrested on March 3 while holding a rally in solidarity with their four colleagues who were detained and jailed in the town of Tuapse in Russia's North Caucasus earlier this week.
The activists unfolded a large banner on the Bolshoi Moskvoretsk Bridge that read: "Free Political Prisoners -- Gazarian, Vetishko, Achilov, Shevchenko!"
A photographer from the independent "Novaya gazeta" newspaper* was also arrested in Moscow with the activists.
The Yabloko activists in Tuapse were sentenced to 7-10 days in jail on February 28 after police arrested them for staging a protest in front of the residence of Krasnodar Krai Governor Aleksandr Tkachev.
They were protesting the deforestation of territory controlled by the governor.
Supporters of the Tuapse activists have been holding public protests since March 2 in Tuapse, Krasnodar, and Moscow.
* CORRECTION: This article mistakenly referred to "Novaya gazeta" as a daily. In fact, the newspaper version is published three times a week.
-- RFE/RL's Russian Service