The court on Tuesday said Navalny's 30-day sentence would come into effect immediately, a Reuters correspondent there reported.
Russian opposition leader Alexei Navalny, who was detained at a recent protest called under the slogan "Putin is not our tsar", walks before entering a court building in Moscow, Russia May 15, 2018.
A verdict was expected from the Moscow court on Friday (May 18), but the case was adjourned for police witnesses to be called.
Navalny was detained at a rally in Moscow on May 5, one of dozens of demonstrations organized by supporters across Russian Federation to protest Putin's inauguration to a new six-year term two days later.
"I consider the detention was illegal, my rights were violated", Navalny said in court, arguing he had a constitutional right to hold a protest.
The anti-corruption campaigner, who has become Putin's most visible political foe, already has served several weeks-long jail terms for organizing other protests.
Around one in 10 of those arrested were minors, according to the organisation.
Navalny had previously been detained in January after joining a rally calling for a boycott of the presidential election.
"30 days of arrest for the right to go out on the street of your city and tell the authorities: "I am not your slave and will never be one". The charge carries a punishment of up to 15 days in custody.
About it Navalny wrote on Twitter.