Sergei Udaltsov, a coordinator for the opposition movement Levy Front (Left Front), was sentenced to 10 days' administrative detention on October 13 after being found guilty of resisting police.
Udaltsov was one of the organizers of the opposition Day of Wrath protest in Moscow the previous day.
Udaltsov told RFE/RL he considered the verdict unjust and would therefore refuse both food and drink.
"I consider the trial was staged. I was not given the opportunity to use my right to a final statement. The judge rejected the video footage that I wanted screened in court. The judge's decisions were based on testimony by police, who told downright lies, claiming I tried to break through the police cordon, that I ignored their orders and tried to escape," Udaltsov told RFE/RL.
Udaltsov was arrested on October 12 after he and other Day of Wrath participants tried to march toward the presidential offices in order to submit their written demands to the presidential chief of staff. The Moscow authorities gave permission for the Day of Wrath, but only as a gathering, not as a march, which is why police stopped the march and arrested several activists.
The Day of Wrath was held under the following slogans: "It Is Time To Change Leaders!" "Rigged Elections Are Illegal!" and "Stop Price Hikes!"
Read more in Russian here