The participants, which include former mayoral candidate and leader of the regional branch of A Just Russia Oleg Shein, are demanding that the results of the election be cancelled.
A Just Russia refused to recognize the victory of United Russia candidate Mikhail Stolyarov, who officially won 60 percent of the vote.
During an unsanctioned March 10 rally attended by about 100 people, Shein said he was the real winner of the election. Officially, Shein received about 30 percent of the vote.
The decision to hold a hunger strike was made after activists trying to submit evidence of falsification were escorted from the Regional Election Commission office by police, the statement by Golos said.
The organization's executive director Lilia Shibanova expressed full support for the protesters, citing mass falsifications in both the December and March elections and the lack of measures taken by authorities to prevent them.
The protesters also submitted an appeal to President Dmitry Medvedev, Prime Minister Vladimir Putin, and several other officials in an attempt to cancel the results the election.