According to the paper, Ruslan Shaveddinov, a spokesman for Navalny's campaign, and Kira Yarmysh, who works for the opposition leader and his foundation, were detained in Moscow on Tuesday on their return from Lithuania.
"The two activists were detained on Tuesday at a Moscow airport after returning from Lithuania, where they had traveled to prevent their live feed from being interrupted by the Russian police," it wrote.
"They were quickly found guilty of breaching rules for demonstrations by giving publicity to a 'voters’ boycott' protest that was held last Sunday. As the protest was unfolding, Mr. Shaveddinov and Ms. Yarmysh were covering it through a live feed on YouTube and on their Twitter accounts."
Shaveddinov was on Wednesday sentenced to eight days in jail and Yarmysh was sentenced to five days in jail.
Navalny, who has been barred from running for president, branded last Sunday's protests a "voters' strike" against Russian President Vladimir Putin's government.
Putin is widely expected to win a fourth presidential term in March.