Lawyers of anti-corruption activist and top blogger Alexei Navalny and opposition leader Ilya Yashin, detained during protests last week, lodged their complaint to the European Court of Human Rights (ECHR).
Both men have been sentenced to 15 days in jail for disobeying police orders during protests in Moscow last Monday against the allegedly fraudulent December 4 parliamentary elections.
"We filed a complaint to the ECHR against violations of several European Convention articles, including poor confinement conditions, in which Yashin and Navalny had to spend more than 24 hours, illegal arrest and the infringement on their rights to express their opinion," Navalny's lawyer, Olga Mikhailova, said.
She added that the defense requested to consider the complaint without delay.
More than 300 protesters, including Yashin and Navalny, were detained during Monday's demonstration at Chistiye Prudy, which gathered some 2,000 people, according to police estimates. Some 70 people remain in custody.
A court sentenced Yashin and Navalny to 15 days of administrative arrest. Their detention is due to end on December 21.
The protest against what many view as widespread vote rigging in favor of Prime Minister Vladimir Putin's United Russia party during the December 4 polls was authorized by the authorities. Police dispersed the demonstration, however, when a crowd began marching towards downtown Moscow, which had not been permitted.